不知道你出的题目是不是如下.看下吧.
1 (m2-3m+2)/(m2+2m-3) = (m-1)(m-2)/(m+3)(m-1) = (m-2)/(m+3)
2 原式= (m-3)(m+2)/(m-3)除(m+3)/(m+3)(m-2) = (m+2)(m-2) = m2-4
又m=1/m , m2=1 原式=1-4=-3
3 由题意 x=2y 原式= (2y-y)/(2y+y)=1/3
4 此题应该是这样吧? x/3=y/4=z/6 有y=4x/3 z=2x (x+y-z)/(x-y+z)= (x+4x/3-2x)/(x-4x/3+2x)=(x/3)/(5x/3)=1/5
第5题未读懂 不好意思