I'm trying to factor -3x 3y-xy + y^2 I know that the first step is to pull out the negative which would leave -(3x-3y+xy-y^2) but I'm not sure where to go from there

One thing to notice is that there's a y^2 term, so a y must show up in both factors. Then note that there's a 3 in front of both an x and a y term, so that means the 3 must not be in the term that has both x and y.

At this point you know the factors must be of the form


-(y \pm 3)(y \pm x)


Now play with the plus or minus signs to see what works. Post back if you're still having trouble.