Question

Let f(x)= 7x-2 and g(x)= sqrt (x) + 2x. what are (f+g)(x) and (f-g)(x)?

Answer 1

•
`(f+g) (x)` =
`9x + √(x) -2`

•
`(f-g)(x)` =
`5x - \sqrt x - 2`

Explanation:

`f(x) = 7x - 2`

`g(x) = √(x) + 2x`

To calculate
`(f+g) (x)` and
`(f-g)(x)`, we have to add and subtract
`f(x)` and
`g(x)` respectively:

•
`(f+g) (x)`

⇒
`f(x) + g(x)`

⇒
`7x - 2 \: + √(x) + 2x`

⇒
`9x + √(x) -2`

•
`(f-g)(x)`

⇒
`7x - 2 - (\sqrt x + 2x)`

⇒
`7x - 2 - \sqrt x - 2x`

⇒
`5x - \sqrt x - 2`