You have to find 2 numbers that multiply to the number without a variable and can also add up to the number that has the variable and once you find them you have to factor them with those 2 numbers found.
when you factor the difference of squares its going to turn out to be a binomial because you have to cross out whatever shows up twice and then finish solving and will be left with multiplying the squares and it will be a number to the second power subtracted by a integer.