Question

x^2+12x+36-y^2 Factor

Answer 1

The factors are of the form (ax + by + c)(dx+ey+f)

Hopefully you can work out a few of those letters immediately (by the coefficients of x^2 and y^2), and then the last few

Answer 2

You look at the first three terms and you factor those three. x^2 + 12x + 36 = (x + 6)(x + 6) which is
(x + 6)^2 then you have
(x + 6)^2 - y^2 so you have the difference of two squares.

(x + 6 + y)(x + 6 - y) is the answer

Answer 3

Damn, I actually prefer your method, but I guess I am used to factorising things where comparing coefficients is the only way and there are no neat tricks such as that.