Ok, so first of all, you need to plug the functions into their places. Since f(x) = 6x and g(x) = x + 3, you'll plug them in accordingly:
(6x) * (x + 3).
Then you'll multiply them together to get 6x^2 + 18x. You can't combine like terms then because of the square in the first term.
So your final answer is 6x^2 + 18x.
I hope this helps you at least a little bit. Thanks for your time!
