Question

Diketahui f(x) = x+2/x-1, x≠1 dan g(x) = 3x-1. nilai (f•g) pangkat -1(-1) = ....
A. 1/6
B. 1/5
C. 1/3
D. 1/2
E. 1

Answer 1

Cari invers masing2 dulu
f^(-1) (x) = (x+2)/(x-1)
g^(-1) (x) = (x+1)/3

berarti :
(f.g)^(-x) = f^-1.g^-1 (x) =
(x+1)/3)+2 ) / (x+1)/3 - 1)) =.
(x+1+6)/3 / (x+1-3)/3 =
(x+7)/3 / (x-2)/3 =
(x+7)/3 .3/(x-2) =
(x+7) / (x-2)

jadi (f.g)^-1(-1) =
(-1+7)/ (-1-2) =
6 / -3 = -2

Answer 2

Jawabannya : A

Semoga bermanfaat...