Doyle, Presiding Judge. Brenda Gates and 283 other plaintiffs sued the Taylor County School District; Superintendent Jennifer Albritton; and current or former Taylor County Board of Education (“School Board”) members Mary Bentley, Ronald Harris, Eloise Doty, Rufus Green II, and Joseph Patterson. The plaintiffs challenged the voting authority of Green and certain resulting acts undertaken by the School Board, and they sought injunctive and other equitable relief. Following a dismissal on the pleadings, the plaintiffs appeal, contending that the trial court erred by concluding that the officer de facto doctrine defeats their challenge to the School Board’s actions. Because the trial court properly ruled that Green was acting as an officer de facto when he cast the votes at issue, we affirm.“We review a grant or denial of a motion to dismiss to determine whether the allegations of the complaint, when construed in the light most favorable to the plaintiff[s], and with all doubts resolved in the plaintiffs['] favor, disclose with certainty that the plaintiff[s] would not be entitled to relief under any state of provable facts.”[1] When, as here, the defendants have moved for a judgment on the pleadings, “[w]e may also consider any exhibits attached to and incorporated into the complaint and the answer, also construing them in the [plaintiffs'] favor.”[2] “A trial court’s ruling on a motion to dismiss is subject to de novo review on appeal.”[3] The complaint alleges that Green was a member of the School Board in November 2013, when the School Board voted to hire Gary Gibson as superintendent of the School District, entering into a contract for a three-year term in December 2013. In March 2015, the School Board voted to employ Green’s daughter-in-law, Shonda Green, as a middle school principal in the School District. In September 2016, while Rufus Green was still acting as a member, the School Board voted to terminate Gibson’s contract early, effective September 20, 2016. In November 2016, the School Board executed a contract with Albritton, employing her to serve a three-year term as superintendent.Green voted in favor of terminating Gibson’s contract and hiring Albritton. The plaintiffs sought to challenge these acts and filed a petition for a writ of mandamus, declaratory judgment, injunctive relief, and for leave to file a writ of quo warranto. They argued that Green’s challenged votes were unauthorized because they occurred after Green’s daughter-in-law was hired as a principal in the School District, citing an anti-nepotism clause in OCGA § 20-2-51 (c) (4) (A). That Code subsection provides: No person who has an immediate family member sitting on a local board of education or serving as the local school superintendent or as a principal, assistant principal, or system administrative staff in the local school system shall be eligible to serve as a member of such local board of education. As used in this paragraph, the term “immediate family member” means a spouse, child, sibling, or parent or the spouse of a child. . . .[4]