g(x) = x² - x - 6
so
g (-4) = (-4)² - (-4) - 6 = 16 + 4 - 6 = 14
When g(x) = 6, we have
6 = x² - x - 6
x² - x - 12 = 0
Solve for x. We factorize this easily as
(x - 4) (x + 3) = 0
which gives
x - 4 = 0 or x + 3 = 0
x = 4 or x = -3
