p := (x^2 - 3*x*y + y^2)^4*(3*x - 7*y + 2)^5;
  q := (x^2 - 3*x*y + y^2)^3*(3*x - 7*y - 2)^6;
  qqq:=gcd(q,p);
  
  factor(qqq);