![](https://iknow-base.cdn.bcebos.com/lxb/notice.png)
急!!!数学题!!
计算:1.(m+2n/n+m)+(n/n-m)-(2m/n-m)2.y/(x-y)^2-x/(y-x)^2...
计算:1. (m+2n/n+m) + (n/n-m ) - (2m/n-m)
2.y/(x-y)^2 - x/(y-x)^2 展开
2.y/(x-y)^2 - x/(y-x)^2 展开
1个回答
展开全部
1.通分
(m+2n)(n-m)/(n+m)(n-m)+n(n+m)/(n+m)(n-m)-(2m)(n+m)/(n+m)(n-m)=(mn-m²+2n²-2mn+n²+mn-2mn-2m²)/(n+m)(n-m)=(3n²-3m²-2mn)/(n+m)(n-m)
2.(x-y)与y-x是相反数 他们的平方相等
∴原式=y/(y-x)²-x/(y-x)²=(y-x)/(y-x)²=1/(y-x)
(m+2n)(n-m)/(n+m)(n-m)+n(n+m)/(n+m)(n-m)-(2m)(n+m)/(n+m)(n-m)=(mn-m²+2n²-2mn+n²+mn-2mn-2m²)/(n+m)(n-m)=(3n²-3m²-2mn)/(n+m)(n-m)
2.(x-y)与y-x是相反数 他们的平方相等
∴原式=y/(y-x)²-x/(y-x)²=(y-x)/(y-x)²=1/(y-x)
推荐律师服务:
若未解决您的问题,请您详细描述您的问题,通过百度律临进行免费专业咨询