Question

If f(x) = 3 + 5x and g(x) = 2x2 – 4, find (f + g)(x).2x2 + 5x – 12x2 – 5x – 72x2 + 5x + 7-2x2 – 5x + 7

Answer 1

From the question

`\begin{gathered} f(x)=3+5x \\ g(x)=2x^2-4 \\ we\text{ want to find } \\ (f+g)(x) \end{gathered}`

This becomes

`\begin{gathered} (f+g)(x)=f(x)+g(x) \\ =3+5x+2x^2-4 \\ collecting\text{ like terms we have } \\ =3-4+5x+2x^2 \\ =-1+5x+2x^2 \\ rearranging\text{ we have } \\ 2x^2+5x-1 \end{gathered}`

Hence the answer is

`2x^2+5x-1`