Question

How do you factor `5a^2 + 3 ab - 8b^2`?

Answer 1

`5a^2+3ab-8b^2 = (a-b)(5a+8b)`

Explanation:

Notice that the sum of the coefficients is zero:

`5+3-8 = 0`

So `(a-b)` is a factor.

The other factor must be `(5a+8b)` to result in the required coefficients of `a^2` and `b^2`.