x^2-y分之y(x-y)-x(x+y)除以x+y分之x^2+y^2.其中x=2,y=-1.先化简再求值.

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x^2-y分之y(x-y)-x(x+y)除以x+y分之x^2+y^2.其中x=2,y=-1.先化简再求值.
x^2-y分之y(x-y)-x(x+y)除以x+y分之x^2+y^2.其中x=2,y=-1.先化简再求值.

x^2-y分之y(x-y)-x(x+y)除以x+y分之x^2+y^2.其中x=2,y=-1.先化简再求值.
x^2-y分之y(x-y)-x(x+y)除以x+y分之x^2+y^2
=[(-x^2-y^2)/(x^2-y)]÷[(x^2+y^2)/(x+y)]
=(x+y)/(y-x^2)
=(2-1)/(-1-2^2)
=-1/5
如果此题是
x^2-y^2分之y(x-y)-x(x+y)除以x+y分之x^2+y^2
=[(-x^2-y^2)/(x^2-y^2)]÷[(x^2+y^2)/(x+y)]
=(x+y)/(y^2-x^2)
=1/(y-x)
=1/(-1-2)
=-1/3
你能明白,赞同

楼主，你描述清楚点，y分之y(x-y)-x(x+y)是[y(x-y)-x(x+y)]/y还是单个的除以y，然后后面又是除以x+y分之x^2+y^2，到底哪些是分子，哪些是分母啊，要不就弄个图片上来。

x^2-(y(x-y)-x(x+y))/y÷(x^2+y^2)/(x+y)
=x^2+(x^2+y^2)/y÷(x^2+y^2)/(x+y)
=x^2+x/y+1
代入数据
=2×2-2+1
=3

=x^2-Y/-(Y^2+X^2)除以（X+Y）/X^2+Y^2
=(Y-X^2)/(X+Y)
= -5

计算:y-x分之x+y+x-y分之y-y-x分之2x-y x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 {(x,y) |x|+|y| x>y?x:y 化简y(x+y)+(x+y)(x-y)-x^2 y-x分之2x-3y-x-y分之x+2y 2x-3y分之y-x-x+2y分之x-y 2分之x+y+3分之x-y；4（x+y）-（x-y)谢谢了, 根号x-根号y分之x+y-x根号y-y根号x分之2xy 2x分之1- x+y分之1(2x分之x+y -x-y)化简计算:x-y分之x+y-x分之y x-y+x+y分之2y的2次方 x-y+x+y分之2y的平方 (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) 因式分解x(x+y)(x-y)-x(x+y)^2 x（x-2y）=y(2y-x) ,则y分之x是多少 {(x,y)|x=2y}交集{(x,y)|y=2分之x}=?