Question

Evaluate ( f g )(x) if f(x) = 3x2 + 3 and g(x) = 3x – 1 when x = 2.

Answer 1

`(fg)(x) = 75`

Explanation:

Given

`f(x) = 3x^2 + 3`

`g(x) = 3x - 1`

Required

Evaluate (fg)(x) for x = 2

In algebra functions

`(fg)(x) = f(x) * g(x)`

Substitute values for f(x) and g(x)

`(fg)(x) = (3x^2 + 3) * (3x - 1)`

Substitute 2 for x

`(fg)(x) = (3*2^2 + 3) * (3*2 - 1)`

`(fg)(x) = (3*4 + 3) * (6 - 1)`

`(fg)(x) = (12 + 3) * (5)`

`(fg)(x) = (15) * (5)`

`(fg)(x) = 15 * 5`

`(fg)(x) = 75`