f(x) 7x'2 - 15x + 9 g(x) 16 x'2 + 8x - 7 ditanya (g•f)

f(x) = 7x² - 15x + 9
g(x) = 16x² + 8x - 7
(g o f)(x) = g(f(x))
= 16(7x² - 15x + 9)² + 8(7x² - 15x + 9) - 7
= 16(49x⁴ - 210x³ + 351x² - 270x + 81) + 56x² - 120x + 72 - 7
= 784x⁴ - 3360x³ + 5616x² - 4320x + 1296 + 56x² - 120x + 65
= 784x⁴ - 3360x³ + 5672x² - 4440x + 1361