# How do you factor #2x²+15x-108#?

##### 2 Answers

Noticing the

Comparing coefficients, we are looking for

I know that

Ultimately, it is always possible to use the general formula when solving quadratics like this, but spotting the factors of the constant term and trying a few possibilities will often get you the answer quicker.

There is another way that doesn't require guessing: the new AC Method to factor trinomials (Google, Yahoo Search)

Converted trinomial:

Compose factor pairs of (a.c = -216). Proceed:....(-8, 27)(-9, 24). This last sum is 24 - 9 = 15 = b. Then, p' = -9 and q' = 24. Back to original

trinomial f(x) (1):

Factored form:

Check: Develop: