若x^2-y^2=40,(x+y)=8/5,则x-y=

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若x^2-y^2=40,(x+y)=8/5,则x-y= 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 若x-y=1 化简（x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)(x^16+y^16) 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若x-y不等于0,2x-3y=0,则分式(10x-11y)/(x-y)的值是（）?(10x-11y)/(x-y) =[(8x-8y)+(2x-3y)]/(x-y) =8为什么8X-8Y=8？(10x-11y)/(x-y)=[(8x-8y)+(2x-3y)]/(x-y)=8+(2x-3y)]/(x-y)=8+0=8 x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 12y(x-y)^2-8(x-y)^3=? 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若x*x+y*y=x+y-1/2,求x,y的值如题 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 （x+2y)(x-2y)-(2y-x)(-2x-y)其中x=8,y=-8 [(x+2y)(x-2y)-(x-2y)^2+8y(x+y)]除以4x= 已知X*X+Y*Y+6X-8Y+25=0 求（Y/X)+(X/Y)-2=? x*x+2x-y*y+6y-8=0,x+y不等于2,求x-y的值 若x^2+y^2-6x+8y+25=0 则y/x-x/y的值是 若x,y为正数,且2*x+8*y-x*y=0,求x+y的最小值