急.(19 11:10:23)已知Y=-2/3,试求分式1+y/y-1 - 4-y/1-y 的值 _数学解答

急.(19 11:10:23)
已知Y=-2/3,试求分式1+y/y-1 - 4-y/1-y 的值

人气：122 ℃　时间：2020-05-27 09:29:09

解答

1+y/y-1 - 4-y/1-y
化简
=(1+y)/(y-1)-(y-4)/(y-1)
=(1+y-y+4)/(y-1)
=5/(y-1)
代入y=-2/3
原式=5/(-2/3-1)=5/(-5/3)=-3