Pull the out from both terms:
You can factor a :
You factored correctly, now simplify:
You can factor a from each term:
Again you can factor more than you did: you can take a out of both terms.
If your terms have more than one thing in common you can factor them all out. If you like, for simplicity and until you get used to the idea, you can take them out one by one. No harm there and it will make checking your work easier. With this last one your only flaw (aside from the parenthesis(!)) was that you didn't go far enough. Both terms still had something you could factor out.