Question

diketahui f(x)= x²-4x-2,g(x)=3x+2 tentukan (fog) (2)​

Answer 1

(fog)(x) = f(g(x))

(fog)(x) = f(3x + 2)

(fog)(x) = (3x + 2)² - 4•(3x + 2) - 2

(fog)(x) = (3x + 2)•(3x + 2) - 4•(3x + 2) - 2

(fog)(x) = (9x² + 6x + 6x + 4) - 4•(3x + 2) - 2

(fog)(x) = (9x² + 12x + 4) - 4•(3x + 2) - 2

(fog)(x) = 9x² + 12x + 4 - 12x - 8 - 2

(fog)(x) = 9x² + 12x - 12x + 4 - 8 - 2

(fog)(x) = 9x² + 0 + 4 - 8 - 2

(fog)(x) = 9x² - 6

(fog)(2) = 9•(2)² - 6

(fog)(2) = 9•4 - 6

(fog)(2) = 36 - 6

(fog)(2) = 30