bilinear transform



Ok, I'm no math-wiz and I just yesterday came across Maxima... but... how do I factor out z in:
z^4*K^4*Q+4*z^3*K^4*Q+6*z^2*K^4*Q+4*z*K^4*Q+K^4*Q+z^4*K^4+4*z^3*K^4+6*z^2*K^4+4*z*K^4+K^4+4*z^4*K^3+8*z^3*K^3-8*z*K^3-4*K^3+6*z^4*K^2-12*z^2*K^2+6*K^2+4*z^4*K-8*z^3*K+8*z*K-4*K+z^4-4*z^3+6*z^2-4*z+1

to get the expression on the form:

A*z^4 + B*z^3 + C*z^2 + D*z + E

Sorry for the embarrasing question...

TIA
/R