Question 118661
In this case, a square is a term that is squared. For instance, the variable x is a term and {{{x^2}}} is a square. So if we have x and y, then {{{x^2}}} and {{{y^2}}} are both squares. Now subtract one from the other to get a difference of squares: {{{x^2-y^2}}}



note: this also works for numbers. For instance, 25 is a perfect square that can be written as {{{5^2}}}. So if we have {{{x^2-25}}} it's the same as {{{x^2-5^2}}} which is also a difference of squares.