Софья9293 3) (y+ 3/8): (7/20-7/8)=4/7
(y+3/8): (14/40-35/40)=4/7
(y+3/8):(-21/40)=4/7
y+3/8=4/7×(-21/40)=-3/10
y=-3/10-3/8=-12/40-15/40
y=27/40
4) (3/4+y):(5/6-8/9)=-9
(3/4+y):(45/54-48/54)=-9
(3/4+y):-3/54=-9
3/4+y=-3/54×-9
3/4+y=27/54
y=27/54-3/4=54/108-81/108
y=-27/108