xy=11,x=2+y,y=x-2,把XY解出来

xy=11,x=2+y,y=x-2,把XY解出来 把多项式（xy-1）^2+(x+y-2)(x+y-2)(x+y-2xy)分解因式,再求值(x=6,y=11) |x|/x+y/|y|+xy/|xy|= f(xy,x-y)=x^2+y^2+xy;f(x,y)/∂x;f(x,y)/∂y x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________? 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? x+y=-3 xy+x+y=-2 x/y+y/x=? (-x+2y)(2x+y)-(2x+y)(y-2x)-3xy=?因式分解 f(x+y,x-y)=(x^2-y^2)/2xy,求f(x,y)! 已知xy-x-y=11,求(xy-1)^2+(x+y-2)(x+y-2xy)的值. 正数x,y满足x-y=2xy,求x-y/x+y的值. f(x+y,x-y)=2xy(x-y),求f(x,y) (x^3-2x^2+xy^2)/(x-y)+(x+y)(y-x)=? 二元二次方程组xy+x+y=11 x^2y+xy^2=30xy+x+y=11 x^2y+xy^2=30 x^2+xy+x=36,y^2+xy+y=20,求x+y. 若x^2+xy+y=14,y^2+xy+x=28,求x+y 函数f(xy,x+y)=x^2+xy+y^2,则df(x,y)=? f(xy,x-y)=x^2+3xy+y^2,则f(x,y)=?