a,b,c-nr.
a:b=2 rest 3
a=b×2+3
a=2b+3
c:(a+b)=3 rest 3
c:(2b+3+b)=3 rest 3
c:(3b+3)=3 rest 3
c=(3b+3)×3+3
c=9b+9+3
c=9b+12
(b+c)-a=289
(b+9b+12)-(2b+3)=289
10b+12-2b-3=289
10b-2b=289-12+3
8b=277+3
8b=280
b=280:8
b=35
a=2b+3
a=2×35+3
a=70+3
a=73
c=9b+12
c=9×35+12
c=315+12
c=327