You may want to review operations on functions first.

If you're asked for (*f* + *g*)(*x*), that's even
easier. You just add the expressions for *f* and
for *g*. For example, if
*f*(*x*) = −2*x*^{2} + 2
and *g*(*x*) = *x*, then (*f*
+ *g*)(*x*) = −2*x*^{2} + 2
+ *x*. Of course, in general you'll need to use the rules for
adding, subtracting, multiplying or dividing polynomials, or
rational functions, or whatever.