You have linear functions $p(x)$ and $q(x)$. You know $p(2)=3$, and $p(q(x))=4x+7$ for all $x$. Find $q(-1)$.
+761 I'm guessing the answer to this question. If we plug in q(-1) into p(q(x)) = 4x+7, we can see that p(q(-1)) = 3. The problem tells us the p(2) is equal to 3. Through this, we can tell that q(-1) is equal to 2.
+170 The assumption in this answer is that p(x) is injective in other words p(x)=p(a)⟹x=a. Since p(x) is linear, it is injective so this solution works.
