Question

(x+3)÷(x-1)>2怎样才能转化为(-x+5)÷(x-1)

Answer 1

答:楼上的答的很好,但是这种方法一开始应该想不到,应该用这个方法:首先:

(-x+5)/(x-1)= [(-x+5+2x-2)-2x+2]/(x-1)=[(x-3)-2(x-1)]/(x-1)

=(x-3)/(x-1) - 2

又因:(x-3)/(x-1) >2 不等式两边同减去2 ,则(x-3)/(x-1)-2>0

即:原不等式 (-x+5)/(x-1)>0