¢1 The instant matter concerns the constitutionality of a statute enacted by the legislature in November, 1999 pursuant to 1999 Okla.Sess. Laws, ch. 217, § 5, codified as 11 0.8.2001, § 22-159. Also at issue are the provisions of two municipal ordinances, Oklahoma City ordinance no. 21,805 and Lawton ordinance no. 99-29, adopted in reliance on the statute. The parties agree we should assume original jurisdiction because this cause involves publict juris issues. Indeed, this Court has assumed original jurisdiction in controversies involving the constitutionality of statutes and public finances. See, e.g., Phillips v. Oklahoma Tax Commission, 1978 OK 34, 577 P.2d 1278 (original jurisdiction assumed when petitioners challenged constitutionality of use tax codified at 68 0.8.Supp.1977, § 14022); City of Tulsa v. State of Oklahoma, 2001 OK 23, 20 P.3d 144 {original jurisdiction assumed when petitioner challenged the applicability of a certain statute to municipal sales and use tax revenues.) The immediacy for assuming original jurisdiction is present because the City of Oklahoma City and the City of Lawton currently collect sales taxes to support public schools in reliance upon the validity of § 22-159. See, eg., Phillips v. Oklahoma Tax Commission, 1978 OK 34, 577 P.2d 1278; State ex rel. Board of Commissioners of Harmon County v. Oklahoma Tax Commussion, 1942 OK 266, 127 P.2d 1052. Accordingly, we assume original jurisdiction over the instant case.
2 Petitioners seek declaratory relief to declare 11 0.$.2001, § 22-159 unconstitutional. Only in rare cireumstances does this Court assume original jurisdiction to grant a form of declaratory relief, Keating v. Johnson, 1996 OK 61, ¶ 12, 918 P.2d 51, 57, citing Ethics Commission v. Cullison, 1998 OK 87, ¶ 4, 850 P.2d 1069, 1072. The instant controversy does not constitute a rare cireumstance in which this Court needs to fashion a remedy or enlarge the seope of its extraordinary declaratory relief.
13 Petitioners also seek a writ of prohibition and/or of mandamus, to prohibit municipal officials from acting in accordance with the two municipal ordinances adopted in reliance on the statute or to mandate that they pursue a different course of action. Since we determine that the two ordinances are authorized, the issuance of a writ is unwarranted.
FACTS AND PROCEDURAL HISTORY
{4 Previously, Respondent City of Ard-more was dismissed pursuant to the application of Petitioner Jack Thompson. On November 6, 2001, we assumed original jurisdiction and denied a temporary injunction against Respondents and a stay of the November 13, 2001, election concerning Oklahoma City Ordinance No. 21,805. Now, we turn to the remaining issues Petitioners raise.
PUBLIC UTILITY BOND ACT
T5 Petitioners argue that § 22-159 is part of the Public Utility Bond Act2 and as such, Const. Art. 10, § 27(B) concerning revenue bonds applies and is violated by § 22-159. We disagree. Section 22-159 appears in the Oklahoma Statutes immediately after the Public Utility Bond Act and provides:
" § 22-159. Municipal support of public school systems
Municipalities may support any public school system located in whole or in part *723within the corporate limits of the municipality, including without limitation by the expenditure of municipal revenues for construction or improvement of public school facilities. In furtherance of municipal support for any public school system, as authorized by this section, the municipal governing body may take all actions necessary to effectuate such support."
The intent of the legislature controls when interpreting statutes. Tulsa County Deputy Sheriff's Fraternal Order of Police v. Board of County Commissioners of Tulsa County, 2000 OK 2, ¶ 10, 995 P.2d 1124, 1125, reh'g. denied, (June 30, 1998), appeal after remand, 2000 OK 2, 995 P.2d 1124. Such intent must be gleaned from the statute in view of its general purpose and object. TXO Production Corp. v. OklL Corp. Comm'n, 1992 OK 39, ¶ 7, 829 P.2d 964, 968. It is presumed that the law-making body has expressed its intent in a statute and that it intended what it so expressed. TXO Production Corp. v. Okl. Corp. Comm'n, 1992 OK 39, ¶ 7, 829 P.2d 964, 969.
17 In analyzing § 22-159, we determine its general purpose is to allow a municipality the option to support public school systems that are located, in whole or in part, within the corporate limits of the municipality. The statute's title, "Municipal support of public school systems," evidences the legislature's intent that this section apply to municipal support of public schools and not to public utilities or to revenue bonds issued to purchase or construct public utilities. The legislature enacted § 22-159 in 1999, pursuant to Section 5 of House Bill No. 1893, and identified this legislation as creating new law, not as amending the 1992 Bond Act. Accordingly, we hold that § 22-159 is not a part of the Public Utility Bond Act and, of necessity, Const. Art. 10, § 27(B) concerning revenue bonds is inapplicable to § 22-159.
CONSTITUTIONAL ISSUES
Sources of Public School Funding
18 Petitioners contend 11 0.8.2001, § 22-159 is unconstitutional in that it violates Art. 18, § 1; Art. 5, § 46 and Art. 21, § 1 of the Oklahoma Constitution.
"In determining the constitutionality of the subject Act, this court is guided in its consideration thereof by well established general precedents. In construing the constitutionality of a statute, the Supreme Court is not authorized to consider its propriety, desirability, wisdom, or its practicability as a working proposition. Those questions are clearly and definitely established by our fundamental law to a certainty as functions of the legislative department of government. The function of the court is clearly limited to the determination of the validity or invalidity of the act. There is a presumption that the Act is constitutional."
Application of Oklahoma Capitol Improvement Auth., 1960 OK 207, ¶¶ 8, 9, 855 P.2d 1028, 1081.
T9 Petitioners argue Const. Art. 13, § 1 limits funding of public school systems to state funds.3 As such, they reason that 11 00.98.2001, § 22-159 is unconstitutional because it provides for municipal support of public school systems. We disagree. Const. Art. 18, § 1 neither discusses nor limits funding sources for public school districts to state funds. If two constructions are possible, one which would uphold the statute and one which would strike it down, it is our duty to apply the constitutional construction. City of Oklahoma City v. Oklahoma Tax Commission, 1990 OK 27, ¶ 10, 789 P.2d 1287, 1292, citing in footnote 11, "State v. Goforth, 772 P.2d 911, 914 (Okla.1989); Earl v. Tulsa County Dist. Court, 606 P.2d 545, 547-48 (Okla.1979)." Petitioners' construction would preclude the well-established procedure whereby counties levy ad valorem taxes to support public school districts pursuant to Const. Art. 10, § 9. Indeed, § 9(b) requires counties to support public school districts. Therefore, Petitioners' argument that Art. 18, § 1 limits funding of public school systems to state funds must fail.
*724General vs. Special Law
$10 Petitioners contend 11 0.8. 2001, § 22-159 constitutes a special law and violates Const. Art. 5, § 46 and § 59.4 Our analysis does not reach the provision contained in § 59 unless we first find that § 22-159 is a special law. In determining whether § 22-159 is a general or special law, we note that. it is a general law if it "relates to persons or things as a class rather than relating to particular persons or things." Grant v. Goodyear Tire & Rubber Co., 2000 OK 41, ¶ 5, 5 P.3d 594, 597, citing Reynolds v. Porter, 1988 OK 88, 114, 760 P.2d 816, 822, Guthrie Daily Leader v. Cameron, 3 Okla. 677, 41 P. 635, 639 (1895). It is a special law if "a part of the entire class of similarly affected persons is separated for different treatment." Grant, 2000 OK 41, 5, 5 P.3d 594 at 597, citing Reynolds, 1988 OK 88, ¶ 14, 760 P.2d 816 at 822. We held in Anderson v. Walker, 1958 OK 297, ¶ 16, 833 P.2d 570, 574 that a law may be general and have a local application or apply to a designated class if it operates equally upon all the subjects within the class for which it was adopted. Section 22-159 concerns municipalities in the state of Oklahoma. It is a general law because no part of the class of municipalities is separated for different treatment, and it relates to all municipalities in the state. Since we determine that § 22-159 is a general law, we need not analyze the statute in the context of Const. Art. 5, § 59 because this provision pertains to special laws. Reynolds v. Porter, 1988 OK 88, ¶ 14, 760 P.2d 816, 822-823.
T11 This statute neither mandates nor precludes municipalities from supporting public school systems located within their corporate limits. Neither does it mandate nor does it preclude municipalities from expending municipal revenues for construction or improvement of public school facilities. Indeed, the statute is permissive in character because the definitive word chosen by the legislature is "may" instead of "shall." "May" denotes a permissive statute. "Shall" signifies a mandatory directive or command. See, e.g., Keating v. Edmondson, 2001 OK 110, ¶ 13, 37 P.3d 882, 888; Samman v. Multiple Injury Trust Fund, 2001 OK 71, ¶ 11, 33 P.3d 302, 307. The statute affords all municipalities in the state of Oklahoma an option to support public school districts located therein, and this option applies equally to each municipality. Whether or not all municipalities choose to exercise this option is of no consequence in our analysis since the statute is general, applies to a designated class, (to-wit: municipalities in the state of Oklahoma,) and operates equally upon all the members of the class (municipalities in the state of Oklahoma) for which it was adopted. Accordingly, § 22-159 does not violate Const. Art. 5, § 46 or Const. Art:5, § 59.
{12 We next address the issue of whether Oklahoma City municipal ordinance No. 21,805 and the City of Lawton municipal ordinance No. 99-29 are general or special laws because of the method in which the ordinances utilize sales tax revenues.
"The decisive question for our determination is whether the act in question was a general law as distinguished from a local or special law. In deciding this question we must look to see if there was a proper and legitimate classification and that such classification was not arbitrary or capricious, bearing a reasonable relationship to the object to be accomplished."
Sanches v. Melvin, 1966 OK 116, ¶ 14, 418 P.2d 639, 641.
{13 Oklahoma City municipal ordinance No. 21,805 apportions sales tax revenues to support public school districts based on the number of students in each school district who live within Oklahoma City and based *725upon need. Independent District No. 89 is comprised solely of students who live in Oklahoma City, whereas the other school districts are comprised of students who live in Oklahoma City and in surrounding suburban areas. The Oklahoma City Metropolitan Area Public Schools Trust (OCMAPST) will act as a conduit for revenues and 70% thereof will go to Independent District No. 89 while 80% will go to twenty-three suburban districts. Independent District No. 89 has ill-equipped and dilapidated school buildings, and thus greater need than suburban districts that have newer, better-equipped facilities. The statute establishes a legitimate and reasonable classification of municipalities statewide that share a situation with a rational relationship to a legitimate legislative objective, to-wit: public school districts that agree to an offer of support from the sales tax revenues collected by the municipalities in which they are located, (either in whole or in part.)
114 Similarly, Lawton municipal ordinance No. 99-29, approved by the citizens of Lawton in a November 9, 1999, election, establishes a sales tax to provide for certain capital improvements on the basis of need, including construction of a new Central Junior High School, (begun September 7, 2000,) to replace a dilapidated facility.
115 The right to free public schools does not guarantee, on its face, equal expenditures per pupil. Fair School Finance Council v. State, 1987 OK 114, ¶ 52, 746 P.2d 1135, 1150 (wherein we used a rational basis standard to evaluate the classification used for expenditures per pupil.) We hold that a rational basis exists for the distinction made in these ordinances regarding which public school districts will receive the sales tax revenues. The apportionment method, (or "classification," utilized by the City of Oklahoma City and the City of Lawton is not arbitrary or capricious, but is reasonable, proper and legitimate. Accordingly, we determine that Oklahoma City municipal ordinance No. 21,805 and Lawton municipal ordinance No. 99-29 are general in nature and do not violate Const. Art. 5, § 46. Since we determine that these ordinances are general in nature, we need not analyze the ordinances in the context of Const. Art. 5, § 59 because this provision pertains to special laws. Reynolds v. Porter, 1988 OK 88, ¶ 14, 760 P.2d 816, 822.
"Educational Institutions"
116 Petitioners' third constitutional argument is that public schools are "educational institutions" under Const. Art. 21, § 15 and thus only the State of Oklahoma can support them. We disagree. Const.Art. 10, § 26 concerns indebtedness of political subdivisions and clearly includes school districts as political subdivisions.6 Although 11 0.9.2001, § 22-159 refers to school systems as opposed to school districts, we determine that the kind of "educational institution" intended by the legislature to be referenced in Const.Art. 21, § 1 is that of a state institution such as a mental health institution, school for the disabled or a center of higher education. These are the types of institutions we previously have recognized as being referenced by Const.Art. 21, § 1. See, eg., St. Louis-San Francisco Ry. Co. v. Morris, 1980 OK 247, 288 P. 306 (state institution for treatment of tuberculosis); Battles v. State ex rel. Oklahoma Commission for Crippled Children, 1951 OK 818, 206 Okla. 444, 244 P.2d 320 (University Hospital); Murrow Indian Orphans Home v. Childers, 1946 OK 187, 197 Okla. 249, 171 P.2d 600 (Indian Orphans Home); Montgomery v. State Industrial Commission, 1942 OK 149, 124 P.2d 726 (state hospital for the insane). Accord*726ingly, we hold that Const. Art. 21, § 1 is inapplicable to 11 0.8.2001, § 22-159, because public school districts are not state "educational institutions."
AUTHORIZATION TO LEVY SALES TAXES
117 Petitioners argue that § 22-159 does not authorize municipalities to levy sales takes to support public schools, because it does not explicitly reference or authorize a sales tax. We disagree. Adequately funded public public schools benefit the entire community in which they are located. As such, they serve a public purpose. Such public schools promote the general welfare, as well as economic development, economic security and prosperity for a municipality. See, eg., State ex rel. Brown v. City of Warr Acres, 1997 OK 117, ¶ 20, 946 P.2d 1140, 1145 (wherein we held "public purpose" embodies a proposal that promotes the general welfare, economic security and prosperity of the city and its citizens); Burkhardt v. City of Enid, 1989 OK 45, ¶ 23, 771 P.2d 608, 614 (wherein we. held "economic development is a public purpose for which a municipality may expend public funds," and determined an institution of higher education provides a public benefit that fosters economic development in a community.) Therefore, we hold that in pursuit of a lawfal public function, the City of Oklahoma City and the City of Lawton enacted the ordinances at issue herein. We further hold that 11 00.98.2001, § 22-159 allows municipalities the option to levy a sales tax for the legitimate public purpose of adequately financing public school systems located in whole or in part within the municipality's corporate limits. A municipality's economic development plan that encompasses improvement of the public school districts located within that municipality serves a legitimate public purpose as contemplated by Const. Art.10, § 14.
€18 "Support," as used in § 22-159, implies financial support, which necessarily implies the power to levy taxes. Therefore, we determine that a sales tax levied by a municipality to support public school districts within its corporate boundary pursuant to 11 ©.8.2001, § 22-159 is permitted under Const. Art. 10, § 26.
Oklahoma City Metropolitan Area Public Schools Trust
119 The City of Oklahoma City has created the Oklahoma City Metropolitan Area Public Schools Trust (OCMAPST) to manage the sales tax revenues collected pursuant to ordinance no. 21,805 and is the beneficiary thereof. Petitioners argue that the OCMAPST attempts to cireumvent Cont. Art. 10, § 26, which limits the indebtedness a city or school district may incur in any calendar year. We disagree. Any indebtedness payable solely from the trust estate and its revenues, incurred by "trustees of trusts for the furtherance of public functions," is constitutional. Morris v. City of Oklahoma City, 1956 OK 202, ¶ 23, 299 P.2d 181, 186-187. We stated therein, "... the fact that such trustees also are designated as regularly constituted authorities of a beneficiary governmental subdivision does not violate sections 26 and 27 of Article X of the Constitution." Morris v. City of Oklahoma City, 1956 OK 202, ¶ 23, 299 P.2d 131, 186-187, citing "Board of County Commissioners of Oklahoma County v. Warram, 285 P.2d 1034, 1085," syllabus 1 8, 7.
120 The plaintiff in Morris advanced an argument similar to Petitioners' herein, to-wit: that Trustees of a public charitable trust are "Agents of the State" and that since the indebtedness of the Trustees is of the type prohibited by Sections 28, 25, 26 and 27 of Art. 10, § 26 of the Constitution, they are void and the Public Trust Law purporting to authorize such indebtedness is unconstitutional. However, we held the contrary, in Morris7 and do so again, today.
*72721 Accordingly, we reiterate our previous conclusion in prior cases that a public trust such as OCMAPST does not violate Art. 10, § 26. Since we determine the actions of the City of Oklahoma City pursuant to § 22-159 are in pursuit of a lawful public function, then the actions of OCMAPST, of necessity, also must be lawful.
CONCLUSION
1] 22 We hold that 11 0.8.2001, § 22-159 is a general law and is not a part of the Public Utility Bond Act. We determine 11 00.98.2001, § 22-159 to be constitutional, and therefore hold that the City of Oklahoma City municipal ordinance No. 21,805 and the City of Lawton municipal ordinance No. 99-29 are authorized sales tax proposals that rely on a constitutional statute and serve a valid public purpose. We conclude that the Oklahoma City Metropolitan Area Public Schools Trust is a lawful entity which performs a lawful and constitutional purpose for the City of Oklahoma City. Finally, we determine that all of Petitioners' arguments lack merit.
ORIGINAL JURISDICTION ASSUMED; DECLARATORY RELIEF DENIED; WRITS OF MANDAMUS AND PROHIBITION DENIED.
Coneur: HARGRAVE, C.J., WATT, V.C.J., HODGES, LAVENDER, SUMMERS (by separate writing), BOUDREAU, JJ. Concurs in result: KAUGER (by separate writing) (joins SUMMERS, J), J. Dissents: OPALA, (by separate Writing) J.. The Public Utility Bond Act, enacted in 1992, effective July 1, 1992, and codified at 11 O.S. 2001, §§ 22-150 et seq., references nine sections, to-wit: §§ 22-150, 22-151, 22-152, 22-153, 22-154, 22-155, 22-156, 22-157 and 22-158. Confusion results from a scrivner's error added by West Publishing in the footnote of § 22-150 that incorrectly identifies § 22-159 as part of the 1992 Bond Act.
. Article 13, § 1 states:
" § 1. Establishment and maintenance of public schools
The Legislature shall establish and maintain a system of free public schools wherein all the children of the State may be educated."
. Const. Art. 5, § 46 and § 59 state in pertinent part:
" § 46. Local and special laws on certain subjects prohibited
The Legislature shall not, except as otherwise provided in this Constitution, pass any local or special law authorizing:
. Regulating the management of public schools, the building or repairing of school houses, and the raising of money for such purposes;"
" § 59. Uniform operation of general laws-Special laws when general law applicable
Laws of a general nature shall have a uniform operation throughout the State, and where a general law can be made applicable, no special law shall be enacted."
. Const. Art. 21, Const.Art. 21, § 1 provides:
"§ 1. Establishment and support
Educational, reformatory, and penal institutions and those for the benefit of the insane, blind, deaf, and mute, and such other institutions as the public good may require, shall be established and supported by the State in such manner as may be prescribed by law."
. Const. Art. 26, § 26 provides in pertinent part:
" § 26. Indebtedness of political subdivisions-Assent of voters-Annual tax-Computation of amount of indebtedness
(a) Except as herein otherwise provided, no county, city, town, township, school district, or other political corporation, or subdivision of the state, shall be allowed to become indebted, .... Provided, that if a school district has an absolute need therefore, ....
. "Such indebtedness is not unconstitutional." Morris v. City of Oklahoma City, 1956 OK 202, 23, 299 P.2d 131, 136 (1956).
"Trusts for the benefit of governmental entities are 'charitable trusts'; and the common law recognizes that the purposes for which such trusts may be established include a broad field of objectives for the benefit of a large class of the public or for lessening the burdens of government."
Morris v. City of Oklahoma City, 1956 OK 202, ¶ 23, 299 P.2d 131, 136 (1955), citing Board of *727County Commissioners of Oklahoma County v. Warram, 285 P.2d 1034, 1955 OK 198, 10, (syllabus 13), 285 P.2d 1034, 1035 (syllabus, T3).