Question

5*(810:9-b*3)=40*8-5

Answer 1

5*(810:9-b*3)=320-5
5*(810:9-b*3)=315
(810:9-b*3)=315:5
(810:9-b*3)=63
90-b*3=63
b*3=90-63
b*3=27
b=27:3
b=9