Решить( 1) 5(x-3)-2-(x-7)+7(2x+6)=7 2) 11(y-4)+10(5-3y)-3(4-3y)=-6 3) 5(8z-1)-7(4z+1)+8(7-4z)=9

1) 5(x-3)-2-(x-7)+7(2x+6)=7
5х-15-2-х+7+14х+42=7
18х=7-42-7+15
18х=-27
х=-27/18=-3/2=-1  1/2
2) 11(y-4)+10(5-3y)-3(4-3y)=-6
11у-44+50-15у-12+9у=-6
11у-15у+9у=-6+12-50+44
5у=0
у=0
3) 5(8z-1)-7(4z+1)+8(7-4z)=9
40z-5-28z-7+56-32z=9
40z-28z-32z=9-56+7+5
-20z=-35
z=-35/(-20)=7/4=1  3/4