Jika (f o g) (x) = 4x²+8x - 3 dan g(x)=2x+4 , maka f-¹(x) =....

jawab :

fog(x) = 4x² + 8x - 3
g(x) = 2x+ 4

g⁻¹ (2x + 4)=  x
2x + 4 = a
x =1/2 a - 2 
g⁻¹ (x) = 1/2 x - 2

f(x) = { fog) o g⁻¹ = 4 (1/2 x -2) ² + 8 ( 1/2x - 2) - 3
      = 4 ( 1/4 x² - 2x + 4)  + 4x- 16 - 3
      = x² - 8x + 16 + 4x - 19
f(x) = x² - 4x - 3