Question

Diketahui f(x) = x2 + 2x + 1 , g(x) = x-1 dan (f o g)(x) = 4 . Nilai x yang memenuhi adalah

Answer 1

F(g(x)) = (x-1)² + 2(x-1) + 1 =4
           = x²- 2x+1+2x-2+1=4
           = x² =4
           = x = 2

Answer 2

F ( x) = x² + 2x + 1
g(x) = x-1
(f o g)(x) = 4

(f o g)(x) = f (g(x))
         4 = f(x-1 )
         4 = (x-1)² + 2(x-1) + 1
         4 = x²-2x+1 + 2x-2 +1
        4 = x²
        x= √4
        x= 2