(810*x+387)/387=91
(810*X+387)=91*387
810*x+387=35217
810*X=35217-387
810 *x =34830
x=34830/810
x=43
(810*x+387)/387=91
(810*X+387)=91*387
810*x+387=35217
810*X=35217-387
810 *x =34830
x=34830/810
x=43