来源:学生作业帮 编辑:百度作业网作业帮 分类:数学作业 时间:2024/06/24 18:40:42
这五道数学题怎么做
![](http://img.wesiedu.com/upload/4/0e/40e58c70ef07d95b42da5b8f5f6c77a3.jpg)
1,=(x+3y-x-2y+2x-3y)/(x^2-y^2)
=2(x-y)/(x+y)(x-y)
=2/(x+y)
2,=(m+2n-n-2m)/(n-m)
=(n-m)/(n-m)
=1
3,=(x-3+x^2-x-6)/x(x-3)
=(x^2-9)/x(x-3)
=(x+3)/x
4,=(a^2+b^2)/(a-b)-(a^2-b^2)/(a-b)
=2b^2/(a-b)
5,=(3x+3y-2x+2y)/(x^2-y^2)
=(x+5y)/(x^2-y^2)