求将x – y = 0,x – 1 = 0,x + y = 0分别变为x – 2 = 0,12x + y – 29 =

已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? x>1,y>0,且满足xy=x^y,x/y=x^3y,求x+y 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值. 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y* 若|x+2y-1|+y²+4y+4=0,求（2x-y）²-2（2x-y)(x+2y)+(x+2y)& x*y'*sin(y/x)-y*sin(y/x)+x=0 求微分方程的解 已知|3x-y|+|x+y|=0,求x-y除以x*y的值. 设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于 已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)X(x-y) 已知x-y/x=x/x-2y(y不等于0),求x：y的值 已知x-y/x=x/x-2y（y不等于0）,求x：y的值