use the quadratics formula to solve (3x + 2)^2 - (8 * 9) = -4x
(3x + 2)^2 - (8 * 9) = -4x expand L side
9x^2 + 12x + 4 - 72 = - 4x simplify
9x^2 + 16x -68 = 0
a = 9 b = 16 c = - 68
\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)
\(x = {-16 \pm \sqrt{16^2-4(9)(-68)} \over 2(9)}\) Plug and chug !
thanks