Question

Jika g(x) = 2x+3 dan (fog)(x) = - 8x2+24x+15/2x+3, maka f(1/2) =...
a.-5
b.-5/2
c.5/2
d.5

Answer 1

G(x)= 2x+3 
g⁻¹(x) = 1/2 (x - 3)

f(x) = fog o g⁻¹ (x)
f(1/2) = (fog)og⁻¹(1/2) = (fog)(- 5/4)
= {-8(-5/4)^2 + 24(-5/4) + 15 }/ {2(-5/4) +3}
= ( 25/2 - 30 + 15) /(1/2)
= 2(25/2 - 15) = -5