(0,02у+4 1/2)*1,3+2,7=8,5
(0,02у+4 1/2)*1,3=8,5-2,7
(0,02у+41/2)*1,3=5,8
0,02у+4 1/2=5,8:1,3 5 4/5:1 3/10=29/5:13/10=29/5*10/13=58/13=4 6/13
0,02у+4 1/2= 4 6/13
0,02у=4 6/13-4 1/2 4 6/13-4 1/2=6/13-1/2=12/26-13/26= -1/26
0,02у= -1/26
у= -(1/26:1/50) - 1/26*50/1=-50/26=-25/13=-1 12/13
у=-1 12/13