Question

For `f(x)=24-2x`, how do you find `f(2)` and `x` such that `f(x) = 10`?

Answer 1

`f(2)=20,x=7`

Explanation:

To evaluate f(2), substitute x = 2 into f(x).

`f(color(red)(2))=24-(2xxcolor(red)(2))`

`color(white)(f(2))=24-4`

`color(white)(f(2))=20`

`"given" f(x)=24-2x" and " f(x)=10`

`"then we can equate the right sides"`

`rArr24-2x=10`

`"subtract 24 from both sides"`

`cancel(24)cancel(-24)-2x=10-24`

`rArr-2x=-14`

`"divide both sides by - 2"`

`(cancel(-2) x)/cancel(-2)=(-14)/(-2)`

`rArrx=7`