2x^2-2xy-x+y/4x^2-1 x^4y^2-x^2y^4/x^2(x+y) 27x^3-y^3/18x^2+6xy+2y^2 b^14-b^7+1/b^21+1
27x^3-y^3/18x^2+6xy+2y^2 2+2=22827x^3-y^3/18x^2+6xy+2y^2