先化简再求值2x/(x²-y²)+x/(y²-x²)+y/[(x-y)(x+y)
先化简再求值:(x-2y)²-(x+2y)(x-2y)-(x-3y)(x-y).其中x²+9y
先化简,后求值[(x-y)²-(x+y)]/(2xy) 先化简,后求值[(x-y)²-(x+y)]/
先化简,在求值:(x-y)²+(3x-2y)(2x+y)-x(6x-y)
(X-Y)²+(3X-2Y)(2X+Y)-X(6X-Y),其中X=½,Y=1(先化简再求值)
因式分解:x²(x-y)+(y-x)
化简求值 【2x²-(x+y)(x-y)][(x+y-1)(x-y+1)+1-2y],其中x=-1,y=-2
化简后求值 [(x-2y)²+(x-2y)(x-2y)-2x(2x-y)]÷2x 其中x=2 y=3
(2x-y)²-4(x-y)(x+2y)
化简:(2x-y)²-4(x-y)(x+y)
化简求值:x-y/x²-2xy+y²-xy+y²/x²-y²,其中(x
先化简再求值 :[(x+2y)²-(x+y)(3x-y)-5y²]÷(2x),其中x=—2,y=5
(x+y)(x-2y)(x²-4y²) 其中x=8 y=-8 化简求值