x^3+y^3=27.x+y=3.求x^2+y^2=?.要有过程的.

已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 已知|x|=2,|y|=3,|x+y|=-(x+y)求x-y (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) x(x-3y)=4y(x-3y),求x:y (x+y)(x+y-10)+25=0,且x-y=3,求x,y (x+y)(x+y-10)+25=0,且x-y=3,求x,y y=3(x-y),x=2(x-y)求x,y的值 已知|3x-y|+|x+y|=0,求x-y除以x*y的值. 已知XY.Y=-3,求-XY(X.X.X.Y.Y.Y.Y.Y.Y.Y-3.X.X.Y.Y.Y.Y.Y-Y)的值.（过程完整） x/3=y/4,求(x*x-xy)/(x*x+y*y)的值 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? x+y/2+ x-y/2=6 2(x+y)-3x+3y=24 求X Y |x|=3 |y|=5 |x-y|=|x|+|y| 求 X+Y和 X-Y 等于多少 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y