Уравнение 12x+18[60-x]=840

Question

Уравнение 12x+18[60-x]=840

Answer 1

12х+1080-18х=840
12х-18х=840-1080
-6х= -240
х= -240:(-6)
х=40

Answer 2

12+1080-18x=840
-18x=840-1080-12
-18x=-252
X=14