Реши уровнение 5*(810:9-х*3)=40*8-5
5*(810:9-x*3)=320-5 5*(810:9-x*3)=315 5*(90-x*3)=315 90-x*3=315:5 90-x*3=63 x*3=90-63 x*3=27 x=27:3 x=9