==> 674 x 4 - a = 1728
2696 - a = 1728
a = 2696 - 1728
a = 968
==> 9000 - 375 x 15 + b = 7134
9000 - 5625 + b = 7134
3375 + b = 7134
b = 7134 - 3375
b = 3759
==> c - ( 85 : 5 x 172 ) = 3985
c - ( 17 x 172 ) = 3985
c - 2924 = 3985
c = 3985 + 2924
c = 6909
==> Succes!