2/5•(х-1,3/5)-0,77=3,1/7
2/5*(x-0.26)-77/100=(31/10)/7
2/5*(x-13/50)-77/100=31/70
2/5*(-13/125)-77/100=31/70
(2/5)x-437/500=31/70
1400x-3059=1550
1400x=1550+3059
1400x=4609
x=4609/1400≈3.292142857
2/5•(х-1,3/5)-0,77=3,1/7
2/5*(x-0.26)-77/100=(31/10)/7
2/5*(x-13/50)-77/100=31/70
2/5*(-13/125)-77/100=31/70
(2/5)x-437/500=31/70
1400x-3059=1550
1400x=1550+3059
1400x=4609
x=4609/1400≈3.292142857