3х-5/7+2х+1/14=  2х-3/2

   3х=5/7-1/14-3/2=(10-1-21)/14=-12/14=-6/7

х=-6/(7*3)=-2/7

ответ

-2/7

Verified answer

3х+2х-2х=5:7-3:2-1:14

3х=10:14-21:14-1:14

3х=-12:14

х=-2:7