Question

For f(x) = 2x² + 3x-10 and g(x) = 3(x-2) find fog (3)

Answer 1

(f o g) = 2(3x - 6)^2 + 3(3x - 6) - 10
(f o g) = 2(9x^2 - 36x + 36) + 9x - 18 - 10
(f o g) = 18x^2 - 72x + 72 + 9x - 28
(f o g) = 18x^2 - 63x + 44

(f o g)(3) = 18(3)^2 - 63(3) + 44
= 162 - 189 + 44
= -27 + 44
= 17