Originally Posted by

**mark** i have a question to do with quadratic equations but what i'm asking isn't really about quadratics but i need to it to complete the question. basically i've been set the question factorise $\displaystyle 54-15x-25x^2$. i know that you have to start by multiplying -25 and 54 which gives -1350. i then have to find two numbers that multiply together to give -1350 but also add together to give -15. is there a method i should use for finding the numbers i'm looking for?

thanks