Question

If f(x)= 2x2 + x - 7 and g(x)= x + 5, then evaluate g(f(3)).

Answer 1

g(f(3)) = 19

Explanation:

This would be your functions:
`\displaystyle{f(x)=2x^2+x-7}` and
`\displaystyle{g(x)=x+5}`. In order to evaluate g(f(3)), we must find the value of f(3) first which we can find by substituting x = 3 in the f(x).

`\displaystyle{f(3)=2(3)^2+3-7}\\\\\displaystyle{f(3)=2\cdot 9 - 4}\\\\\displaystyle{f(3)=18-4}\\\\\displaystyle{f(3)=14}`

Therefore, g(f(3)) is basically equal to g(14), we substitute x = 14 in the g(x).

`\displaystyle{g(f(3))=g(14)=14+5 = 19}`

Hence, g(f(3)) is 19.