(gof) (-3) adalah?? beserta caranya

f(x) = 2x - 1
g(x) = x² + 6x + 9

(g o f) (x) = (2x - 1)² + 6(2x - 1) + 9
(g o f) (x) = 4x² - 4x + 1 + 12x - 6 + 9
(g o f) (x) = 4x² + 8x + 4

(g o f) (-3) = 4(-3)² + 8(-3) + 4
(g o f) (-3) = 36 - 24 + 4
(g o f) (-3) = 16