1) ... (29-2х) : 3=6+1; 29-2х=7×3; -2х=21-29; -2х=-8; х=4
2) ... 280 : (6y-13)=63-7; 6y-13=280/56; 6y-13=5; 6y=18; y=3
3) ... 4*(7x+1)=135+9; (7x+1)=144/4; 7x+1=36; 7x=36-1; x=35/7; x=5
4) ... (192-13y) *7=180-19; 192-13y=161/7; 192-13y=23; -13y=23-192; -13y=-169; y=13
Вот.