If $\(a \clubsuit b = a^2 + 2ab + b^2\)$ and $\(2 \clubsuit x = 81\)$, find the sum of all possible values of $x$.
22 + 2*2*x + x2 = 81
x2 + 4x + 4 = 81
x2 + 4x - 77 = 0
(x + 11)(x - 7) = 0
x = -11 and x = 7
I’m sure you can sum these yourself!