|x-2|+|y-2|=0,求xy= ,|x|=-|y-7|,则xy= 拜托

xy=-2,x+y=3,求代数式（4xy+12y)+[7x-(3xy+4y-x)] 若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值 已知y-x-2xy=0,求3x+xy-3y/y-xy-x的值 已知y-x-2xy=0,求(3x+xy-3y)\(y-xy-x)的值 已知x²-7xy+12y²=0求x²-xy+y²/2xy的值 已知x-xy=8,xy-y=-9,求x+y-2xy的值 已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? x^2+xy+x=36,y^2+xy+y=20,求x+y. 如果x^2+xy+y-14,y^@+xy+x=28,求x+y的值. 已知X+y=6,xy=7 求x^2y+xy^2= 已知x=3y,试求(x-y)^2+2xy-y^2/x^2+7xy+y^2