I have to factor 15x^2+2x-24 How can I do this?

(5x - 6)(3x + 4)

I got that by trial and error. Here's how.

The coefficients of x have to have a product ot 15. I chose 5 and 3.
The constant terms in the factors must have a product of -24. I tried -6 and 4.
The two "cross products" have to add up to two.
It worked