A College Park development authority agreed to sell land to College Park MOB under a purchase agreement containing reconveyance and right-of-first-refusal provisions. The authority appealed summary judgment for the buyer on its specific-performance claim and on the authority’s counterclaims. The Court of Appeals of Georgia held that the trial court’s analysis of specific performance was incomplete, so summary judgment on that claim was improper. The court rejected the authority’s remaining challenges, including its mutual-mistake theory, because the authority did not address the required negligence or prejudice analysis and had not shown that the defense defeated summary judgment. The court therefore reversed the specific-performance ruling and affirmed the judgment on the counterclaims.