Find all values $a$ for which there exists an ordered pair $(a,b)$ satisfying the following system of equations: \begin{align*} a + ab^2 & = 40b, \\ a - ab^2 & = -32b. \end{align*} List only the values for $a.$
The values of a are 8 and -8.
OP, try adding the two equations and see if you can find a value for b in terms of a. Then substitute that value back into the system.
