Remember how to factor something like ?

Remember the middle term (-5x) is the sum of the product of the coefficient of the first and last term. So in this case the only numbers that would add up to -5 (coefficient of middle term) and whose product would be +6 would be -3 and -2. So from here, you could expand the expression as

There should be a common factor in both pars (x-3). I do not want to give you the answer (sorry!). Hopefully, this will trigger your memory.