For the polynomial $x^2-(k+2)x+(k-1)$, the sum of the zeroes is 7. What is the PRODUCT of the zeroes?

Sum $=-\frac{b}{a}=k+2$. Setting $k+2=7$ gives $k=5$, so the constant term is $k-1=4$ and the product $=\frac{c}{a}=4$. (The polynomial is $x^2-7x+4$.) 5 stops at the value of $k$; 7 just repeats the sum; 6 uses $k+1$ in place of $k-1$.