The equation is

which I would probably write

so as to get the coefficient of the highest power of to be one. I don't think factoring is going to be the best way to solve this problem. You'd have to come up with two numbers whose product is -2, and which add up to -5. You could, of course, set up two simultaneous equations:

and solve. But that's adding another quadratic equation to solve, which seems a bit silly.

Have you done completing the square, or the quadratic formula yet?