this one is giving me trouble.

$\displaystyle 3p^2-50y^2-25yp+7p+2$

I try some normal things and get nowhere...

$\displaystyle (3p+5y)(p-y10)+7p+2$

$\displaystyle (3p+1)(p+2)-25yp-50y^2$

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.

$\displaystyle (p+3)^2-(p+5y)^2 + 3p^2 +p -7 -15yp -25y^2$

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.