4(х-5)/12 - 3(х-7)/12
--------------------------- =-3/4
3(х+5)/18 - 6(х-7)/18
(4х-20-3х+21)/12
------------------------- = -3/4
(3х+15- 6х+42)/18
х+1 /12
------------- = -3/4
57-3х/18
х+1 /12
----------------- = -3/4
-3(х+19)/18
х+1 /12
------------- = -3/4
-(х+19)/6
х+1 /12=-3/4*(-(х+19)/6)
х+1 /12=х+19 /4*2
х+1 /12=х+19 /8
8*(х+1) = 12*(х+19)
8х+8=12х+228
8-228=12х-8х
4х=-220
х=-55