Hi guys
it was simple after all
to refresh the problem, it was:
find h and k so that both: x-3 and x+2 are factors of x^4-x^3+hx^2+kx-6
so i stored x^4-x^3+hx^2+kx-6 in p(x)
and then did solve(p(3)=0 and p(-2)=0,{h,k})
and worked perfectly
that's all.