Question

Which expression represents the composition [f o g](x) for the functions below? f(x) = 2x + 3 g(x) = x – 6

2x – 9
2x – 3
2x – 15
2x2 – 9x – 18

Answer 1

The answer would be 2x-9. If you need help to see how to work it out, let me know 

Answer 2

Option A is correct

2x-9

Explanation:

Given the functions:

f(x) = 2x + 3

g(x) = x -6

We have to find [f o g](x).

`[fog](x) = f[g(x)]`

Substitute the function g(x),

`[fog](x) = f[x-6]`

Replace the value of x with x-6 in f(x) we have;

`[fog](x) =2(x-6)+3`

⇒
`[fog](x) =2x-12+3`

⇒
`[fog](x) =2x-9`

Therefore, the value of
`[fog](x)` is, 2x-9