Concept:Solve the given equation by expanding and simplifying to isolate q.Explanation:Start with 18(p+q)=(18+p)q.Expand both sides: 18p+18q=18q+pq.Subtract 18q from both sides: 18p=pq.Since p is nonzero, divide both sides by p: q=18.Therefore, the statement that must be true is q=18.Answer:A. q=18