若x^2-y^2=30,x+y=6/5,求x-y的值急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需急需我需要过程，擦，

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 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*y)的值 若5x+3y=3x+4y=x+2y+6,则x+y=___ 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 X^2-Y^2+6X+10Y-30=0 X^2+Y^2-5X-8Y+21=0 X=?Y=? 若x,y∈R,(x+y)^2i+6i-x=-y+5(x+y)i-1,求x和y的值 3x+5y-(x+y)=6 2(x+y)-3x=-7 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值 若x+y分之x-y=3,求式子x+y分之5(x-y)—2(x-y)分之x+y的值 若x-y分之x+y=3,求式子x+y分之5(x-y)—2（x-y）分之x+y的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值