(1)-m^2+2m-1/1-m^2 (2)y^2-2xy+x^2/x^2-y^2 (3)(x-y)^2(a+b)/(y-x)^3(a^2-b^2)

(1)-m^2+2m-1/1-m^2=-(m^2-2m+1)/1-m^2=-(1-m)^2/(1+m)(1-m)=-(1-m)/(1+m)=(m-1)/(m+1)
(2)y^2-2xy+x^2/x^2-y^2 =(x-y)^2/(x+y)(x-y)=(x-y)/(x+y)
(3)(x-y)^2(a+b)/(y-x)^3(a^2-b^2)=(x-y)^2(a+b)/(y-x)^3(a-b)(a+b)=1/(y-x)(a-b)
希望你能采纳，谢谢！

（1）(-m^2+2m-1)/(1-m^2)
解，原式=[-(m-1)^2]/(1-m)(1+m)
=(m-1)^2/(m-1)(m+1)
=(m-1)/(m+1)
(2)(y^2-2xy+x^2)/(x^2-y^2)
解，原式=（x-y）^2/(x-y)(x+y)
=(x-y)/(x+y)
(3))(x-y)^2(a+b)/(y-x)^3(a^2-b^2)
解，原式=（y-x）^2(a+b)/(y-x)^3(a+b)(a-b)
=1/(y-x)(a-b)

我打中文过程然后你自己理解了之后写出答案吧，这种题不难，一定要拿分。
(1) 注意看分子，将负号拿出来以后是m^2-2m+1，可以用平方公式变成-（m-1）^2，然后分母又是(1-m)(1-m)约掉,答案就是(m-1)/(m+1)
(2)道理和第一题一样,分子是(y-x)^2 分母是(x-y)(x-y) 约掉一个改变符号,答案(-y+x)/(x-y)=1
(3)首先把分子的a+b和分母的(a^2-b^2)约成分母一个a-b..然后分母的三次方如果你一时间看不出来,把它变成(y-x)(x-y)^2, 就很容易看出来了 答案1/(y-x)(a-b)
看不懂继续问 我高中的

(1)应该是(-m^2+2m-1)/(1-m^2)吧？
=-(m²-2m+1)/[(1-m)(1+m)]
=-(m-1)²/-[(m-1)(m+1)]
=(m-1)/(m+1)
(2)同（1）吧？
=(x-y)²/[(x+y)(x-y)]
=(x-y)/(x+y)
(3))(x-y)^2(a+b)/(y-x)^3(a^2-b^2)
=[(y-x)²(a+b)]/[(y-x)³(a+b)(a-b)]
=1/[(y-x)(a-b)]

1. (-m^2+2m-1)/(1-m^2)=-(m-1)^2/[(1+m)(1-m)]=(m-1)/(m+1)2. (y^2-2xy+x^2)/(x^2-y^2)=(x-y)^2/[(x-y)(x+y)]=(x-y)/(x+y)3.[ (x-y)^2(a+b)]/[(y-x)^3(a^2-b^2)]=[(y-x)^2*(a+b)]/[(y-x)^3*(a+b)*(a-b)]=1/[(y-x)*(...

1. (-m²+2m-1)/(1-m²)
=-(m-1)²/[(1+m)(1-m)
]=(m-1)/(m+1)
2. (y²-2xy+x²)/(x²-y²)
=(x-y)²/[(x-y)(x+y)
]=(x-y)/(x+y)
3.[ (x-y)²(a+b)]/[(y-x)³(a²-b²)]
=[(y-x)³*(a+b)]/[(y-x)³*(a+b)*(a-b)]
=1/[(y-x)*(a-b)]