3(2y-1)+6(3y-4)=83+5(y-3)
3×2y-3+6×3y-6×4=83+5y-5×3
6y-3+18y-24=83+5y-15
(6+18)y-(3+24)=68+5y
24y-27=68+5y
24y-5y-27+27=68+27+5y-5y
24y-5y=68+27
(24-5)y=95
19y=95
y=95:19
y=5
Ответ: 5
Проверка:
3(2×5-1)+6 (3×5-4)=83+5(5-3)
3(10-1)+6(15-4)=83+5×2
3×9+6×11=83+10
27+66=93
93=93