帮忙做2个题 (x+y+1)(x+y-1) (2x-y-3)²
分解公因式2题(x-2y+3y)²(-x+y)(-y-x)(-2x²+1/2)(-2x²-
(x+2y)²-2(x-y)(x-y)+2y(x-3y)帮忙化简下,准确一点哦,
1-x²+2xy-y²
计算:(1).(-2xy²)*(3x²y)²
证明下列极限不存在(1) Lim x+y/x-y (2)lim x²y²/ x²y&sup
化简,并求值2(x-2y)²-4(x+3y)(x-3y)-2(x-y).(y+x)-5(-x-1)²
3y/2x+2y+2xy/x²+xy 2x/x²-64y²-1/x-8y (1/a+1/b
求代数式3x²y+5x-0.5x²y+3.5x²y-2的值,其中x=1/5,y=7
因式分解:4x²-y²-2y-1
再求代数式(4x²-7x+6y-1)-(-2x²+3y²+2y+2x)+(-6x²
(x+y-2xy)(x+y-2)+(1-xy)²
请给位大师帮忙做下这几道题:1.(x+y)(x+y)-2 2.(x²-x)²-14x²+1