已知xyz≠0且2x3y=3x-8y=z，求(xy-2z)/(x-y2z)的值

更新时间：2022-06-08 11:17:07 75次访问

已知xyz≠0且2x+3y=3x-8y=z，求(x+y-2z)/(x-y+2z)的值

2x+3y=z..........1

3x-8y=z...........2

1式乘8加2式乘3，得

25x=11z

x=11z/25

代入1式，得

2*11z/25+3y=z

3y=3z/25

y=z/25

所以

(x+y-2z)/(x-y+2z)

=(11z/25+z/25-2z)/(11z/25-z/25+2z)

=(-38z/25)/(60z/25)

=-38/60

=-19/30