Question

Functions f , g: R → R are defined, respectively, by f(x) = x 2 + 3x + 1, g(x) = 2x – 3, find f o g

Answer 1

Given, f(x) = x² + 3x + 1, g(x) = 2x – 3

fog = f(g(x))

= f(2x – 3)

= (2x – 3)² + 3(2x – 3) + 1

= 4x² + 9 – 12x + 6x – 9 + 1

= 4x² – 6x + 1