Diketahui f(x) = x^5 + 10 dan g(x) = 2x + 5. Nilai (gof^(-1) o fog^(-1) )(1) =.... (A) 0 (B) 1 (C) -1 D)3/2 E. tak hingga

jawab

f(x) = x⁵ +10
x⁵ = y - 10
x= ⁵√(y-10)
f⁻¹ (x)= ⁵√(x-10)

g(x)= 2x+5
2x = 5 - y
x = (5- y)/2
g⁻¹(x)= (5 - x)/2

(gof⁻¹) o (fog⁻¹)  (x) =
= g o [f⁻¹{fo g⁻¹}] (x)
= g og⁻¹ (x)
= 2(5- x)/2 + 5
= 5-x + 5
=  - x
= - 1