 ring r=0,(x,y,z),dp;
poly f=(3x+6y)^5;
f/5;
==> 243/5x5+486x4y+1944x3y2+3888x2y3+3888xy4+7776/5y5
cleardenom(f/5);
==> x5+10x4y+40x3y2+80x2y3+80xy4+32y5
vector w= [4x2+20,6x+2,0,8]; // application to a vector
print(cleardenom(w));
==> [2x2+10,3x+1,0,4]
