first question on this website

Let's turn $a$ into $s$, to not get confused with another $a$. We can see that $9x^2 + 24x + s = (ax)^2 + abx + abx + b^2$. This equals $(a^2)x^2 + (2ab)x + b^2$. We have that $9 = (a^2)$, $24 = (2ab)$, and $s = b^2$. By $9 = (a^2)$, $a = 3$. If $a = 3$, we can see that $b = 4$. Then, we can get that $s = 16$. So your answer would be $a = 16$. 

- Daisy

thanks!