You can put this solution on YOUR website! So am I ... since you didn't include in your post what it is you are supposed to do with the expression. Factor it? Find its zeros? Determine its degree? Other?
Please re-post your question and include the instructions for what you are supposed to do with the expression.
P.S. I assumed that a3 meant . If so, then please post exponents using the "^" character: a^3. (and if an exponent is more than just a number or a variable, like then post the exponent in parentheses: a^(x+3).