this one is giving me trouble.

I try some normal things and get nowhere...

so I try to make perfect squares and fold them together as difference of squares. but to do this given the coefficients I have to start adding, subtracting and splitting terms.

at this point Im not sure what to do. I think I could keep going for ever like this and I see no pattern to fold everything together.

I know it can be factored by the CAS into 2 factors with 3 terms each.