This is very similar to evaluating
functions. There's one thing to keep in mind, though. If
you see *f*(*x* + 2), that means to plug (*x* +
2) into the function. (I recommend putting it in parentheses, so
you'll remember that it's one unit.) If you
see *f*(*x*) + *f*(2), on the other hand, that
means to plug *x* into the function, *and* to plug 2
in separately, and to add the results.