Question

Diberikan f(x) = x³ - 1 dan g (x) = x + 1. nilai (f°g)(-5) = ​

Answer 1

Jawaban:

(f o g)(x) = f(g(x))

f(x) = x³ - 1

f(g(x)) = (g(x))³ - 1

f(g(x)) = (x + 1)³ - 1

= (x + 1)(x + 1)(x + 1) - 1

= (x² + 2x + 1)(x + 1) - 1

= x³ + 3x² + 3x + 1 - 1

= x³ + 3x² + 3x

jadi (f o g)(x) = x³ + 3x² + 3x

(f o g)(5) = (-5)³ + 3(-5)² + 3(-5)

= -125 + 3(25) - 15

= -125 + 75 - 15

= -65

^J^