Jika g(x) = 4x + 1 dan (fºg)(x) = 8x + 11, nilai f-1(-7) = …​

g(x) = 4x + 1

(f○g)(x) = 8x + 11

(f○g)(x) = f(g(x))

8x + 11 = f(4x + 1)

misal : 4x + 1 = t sehingga x = (t – 1)/4

8(t – 1)/4 + 11 = f(t)

2(t – 1) + 11 = f(t)

2t – 2 + 11 = f(t)

2t + 9 = f(t)

f(x) = 2x + 9

misal : f(x) = y

y = 2x + 9

2x = y – 9

x = (y – 9)/2

f^-1(x) = (x – 9)/2

f^-1(-7) = (-7 – 9)/2

f^-1(-7) = -16/2

f^-1(-7) = -8