Question

How do you factor `6x^2 - 18xy - 24y^2`?

Answer 1

6(x + y)(x - 4y)

Explanation:

`f(x,y) = 6f'(x,y) = 6(x^2 - 3xy - 4y^2).`
To factor the trinomial f'(x,y) in parentheses, consider x as variable and y as a constant.
Since a - b + c = 0, use shortcut. The 2 factors are: (x + y) and (x + c/a = (x - 4y)
f'(x,y) = (x + y)(x - 4y)
f(x,y) = 6(x + y)(x - 4y)