What I mean by the complete way is this example:
x^2 - 12x + x - 12
x^2 - 12x + x - 12
x (x - 12) - 1(x - 12)
(x - 12) (x + 1)
x^2 - x + 12x - 12
x^2 + 11x - 12
These are the problems that I'm stuck on:
1. 5x^2 - 80
2. x^2 - 100
3. x^3 - 3x^2 + 4x
4. 81x^2 - 1
5. x^2 + 13x - 30