bagaimana cara kerjanya?

fog(x) = 3x² - 16x + 12
f(2 - x) = 3x² - 16x + 12
f(-1) = ...
2 - x = -1
2 + 1 = x
x = 3
f(3) = 3(3)² - 16(3) + 12 = 27 - 48 + 12 = -9

(f o g)(x) = 3x^2 - 16x + 12
f(g(x)) = 3x^2 - 16x + 12
f(2 - x) = 3x^2 - 16x + 12
Misal a = 2 - x => x = 2 - a
f(a) = 3(2 - a)^2 - 16(2 - a) + 12
f(-1) = 3(2 - (-1))^2 - 16(2 - (-1)) + 12
= 3(3)^2 - 16(3) + 12
= 27 - 48 + 12
= -9