Question

80*b-3*90+430=1600/2

Answer 1

80*b-3*90+430=1600:2
80*b-270+430=800
80*b-270=800-430
80*b-270=370
80*b=370+270
80*b=640
b=640:80
b=8
проверка
80*8-3*90+430=1600:2
640-270+430=800
370+430=800
800=800