jika f(x) = x+3,(gof) (x) =2x²-4x-3 maka (fog) (1)

f(x) = x + 3
(gof) (x) =2x² - 4x - 3

g(f(x)) = 2x² - 4x - 3
g(x + 3) = 2x² - 4x - 3
g(x) = 2(x - 3)² - 4(x - 3) - 3
g(x) = 2(x² - 6x + 9) - 4x + 12 - 3
g(x) = 2x² - 12x + 18 - 4x + 9
g(x) = 2x² - 16x + 27

fog(x)
= f(g(x))
= 2x² - 16x + 27 + 3
= 2x² - 16x + 30

fog(1) = 2(1)² - 16(1) + 30
           = 2 - 16 + 30
           = 16