500-[(1460-a*4)/10+431]/3=353
[(1460-a*4)/10+431]/3=-500-353
[(1460-a*4)/10+431]/3=-147
[(1460-4a)/10+431]= -147/3
[(1460-4a)/10+431]= -49
(1460-4a)/10=-431-49
(1460-4a)/10= -490
1460-4a= -480/10
1460-4a= -48
-4a=-1460-48
-4a= -1508
-a = -1508/-4
-a = 377
a=1/377
