Question

Diketahui f(x)=x^2+4x-5 dan g(x)=ax+1 jika (gof)(-1)=-15. Tentukan nilai a
tolong ya. dikumpulin sekarang

Answer 1

F(x)= x²+4x-5
g(x)= ax+1

(gof)(-1)= -15 ; nilai a=...?

(g o f)(x)= ...?
= g(f(x))
= g(x²+4x-5)
= a(x²+4x-5)+1

(g o f)(-1)
= a(x²+4x-5)+1
= a((-1)²+4(-1)-5)+1
= a(1-4-5)+1
= a-4a-5a+1
= -8a+1

(g o f)(-1)= -15
-8a+1 = -15
-8a = -15-1
-8a = -16
   a = 2