4х-3у=-1
х-5у=4 /-4
-----------------
4х-3у=-1
-4х+20у=-16
------------------
17у=-17
у=-1
х - у=3 /-3
3х+4у=2
-------------
-3х+3у=-9
3х+4у=2
---------------
7у=-7
у=-1
х+у=6 /-5
5х-2у=9
-------------
-5х-5у=-30
5х-2у=9
--------------
-7у=-21
у=3
2/х+4=7/2х-1
4х-2=7х+28
4х-7х=28+2
-3х=30
х=-10
х+1/2-5х/12=3/4
6х+6-5х=9
х=3
2-3(х+2)=5-2х
2-3х-6=5-2х
-х=9
х=-9