Page 530 p1:=subs({ d0=c0,d1=c1,a0=b0*c0+3*b1*c1, a1=b0*c1+b1*c0+2*b1*c1},p123): p1:=simplify(p1); p2:=subs({ d0=c0,d1=c1,a0=b0*c0+3*b1*c1, a1=b0*c1+b1*c0+2*b1*c1},p12): p2:=2*simplify(p2);%ad# for emphasis p3:=subs({ d0=c0,d1=c1,a0=b0*c0+3*b1*c1, a1=b0*c1+b1*c0+2*b1*c1},p23): p3:=simplify(p3); p4:=subs({ d0=c0,d1=c1,a0=b0*c0+3*b1*c1, a1*b0*c1+b1*c0+2*b1*c1},pdis): p4:=simplify(p4);