M•80=539+21, 450:(r-8)=3 ,83-29=b•27

M•80=539+21

м*80= 560

м=560/80

м=7

 450:(r-8)=3

r-8=450/3

r-8=150

r=150+8

r=158

83-29=b•27

b*27=54

b=54/27

b=2