Помогите 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

5 х-15-2-х+7+14 х+42=7

18 х=7-42-7+15

18 х=-27

х=-27/18=-3/2=-1 1/2

2) 11 (y-4) + 10 (5-3y) - 3 (4-3y) = - 6

11 у-44+50-15 у-12+9 у=-6

11 у-15 у+9 у=-6+12-50+44

5 у=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