Question

(38+b)*12=840
Решу уравнение

Answer 1

(38+b)*12=840
(38+b)=840:12
(38+b)=120
b=120-38
b=92
(38+92)*12=840

Answer 2

перерешай

Answer 3

(38+b)=840:12
38+b=70
b=70-38
b=32
(38+32)*12=70*12=840