Question

If `f (x) = 2 + x` ; `g(x) = x^2 + 5`, then what is (f - g)(-5)?

Answer 1

`(f-g)(-5)=-23`

Explanation:

If
`color(white)("XXX")color(green)(f(x))=color(green)(2-x)`
and
`color(white)("XXX")color(blue)(g(x))=color(blue)(x^2+5)`
then
`color(white)("XXX")(color(green)f-color(blue)g)(color(red)x)=(color(green)(2-color(red)x))-(color(blue)(color(red)x^2+5))`

`color(white)("XXXXXXXXX")=-(color(red)x^2+color(red)x+3)`
and
`color(white)("XXX")(f-g)(color(red)(-5))=-(color(red)((-5))^2+color(red)((-5))+3)`

`color(white)("XXXXXXXXXX")=-(25-5+3)`

`color(white)("XXXXXXXXXX")=-23`