-7-5z=4-3z
-7-4=5z-3z
-11=2z
z=-11:2
z=-5,5
-2/3х+1(1/6)=1,5х+1
1(1/6)-1=1,5х+2/3х
1/6=15/10х+2/3х
1/6=(15*3+2*10)/30х
1/6=65/30х
х=1/6:65/30
х=30/(6*65)
х=5/65
х=1/13
1/2у-1/3=5/18-8/9у
1/2у-8/9у=5/18+1/3
(2*9-2*2)/18у=(5*1+1*6)/18
14/18у=11/18
у=11/18:14/18
у=11/18 * 18/14
у=11/14