Question

If f(x) = –2x + 7 and g(x) = x2 – 2, what is [f o g](3)?
–7
–1
1
7

Answer 1

`f(x)=-2x+7\\\\g(x)=x^2-2\\\\\ [f\ \circ\ g](x)=-2(x^2-2)+7=-2x^2+4+7=-2x^2+11\\\\\text{Put x = 3 to the equation of the function}\\\\\ [f\ \circ\ g](3)=-2(3^2)+11=-2(9)+11=-18+11=-7\\\\Answer:\ \boxed{-7}`

Answer 2

The value of [f o g](3) is -7

Explanation:

Given two functions

`f(x)=-2x+7, g(x)=x^2-2`

we have to find [f o g](3)

`f(x)=-2x+7`

`[f o g](x)=f(g(x))=f(x^2-2)=-2(x^2-2)+7`

`[f o g](x)=-2x^2+4+7=-2x^2+11`

Put x=3

`[f o g](3)=-2(3)^2+11=-7`

The value of [f o g](3) is -7

Option 1 is correct