а)5х+3(х-1)=6х+11

5х+3х-3=6х+11

5х+3х-6х=3+11

2х=14

Х=14:2

Х=7

в)6х+11=5х+3(х-1)

6х+11=5х+3х-3

6х+11=8х-3

6х-8х=-11-3

-2х=-14(×(-1))

2х=14

х=14÷2

х=7

б)8(y-7)-3(2y+9)=15

8у-56-6у-27=15

2у=98

у=49

г)0,5(2y - 1) - (0,5 - 0,2y) + 1 = 0;

0.5 * 2y - 0.5 * 1 - 0.5 + 0.2y + 1 = 0;

y - 0.5 - 0.5 + 0.2y + 1 = 0;

y + 0.2y = 0.5 + 0.5 - 1;

1.2y = 0;

y = 0.