(fog) (x) = x^2+3x+4 dan g(x) = 4x-5 tentukan nilai dari f(3)!

Fungsi Komposisi , Kelas 10

fog(x) = x² + 3x + 4
f(g(x)) = x² + 3x + 4
f(4x - 5) = x² + 3x + 4

f(3) ?

4x - 5 = 3
4x = 8
x = 2

f(3) = 2² + 3(2) + 4
= 4 + 6 + 4
= 14

Diketahui :
(fog)(x) = x² + 3x + 4
     g(x) = 4x-5

Misalkan :
=> 4x - 5 = a
=>        x = (a + 5)/4

(fog)(x) = x² + 3x + 4
  f(g(x)) = x² + 3x + 4
 f(4x-5) = x² + 3x + 4

     f(a) = ((a+5)/4)² + 3((a+5)/4) + 4
     f(3) = ((3+5)/4)² + 3((3+5)/4) + 4
     f(3) = (8/4)² + 3(8/4) + 4
     f(3) = (2)² + 3(2) + 4
     f(3) = 4 + 6 + 4
     f(3) = 14