6x+6x+300=2700 => 12x=2400 = x=200
6х+ 6(х + 50)=2700
6х +6х +300=2700
12х + 300=2700
12х=2700:300
12х=9
х=12-9
х=3
6x+6x+300=2700 => 12x=2400 = x=200
6х+ 6(х + 50)=2700
6х +6х +300=2700
12х + 300=2700
12х=2700:300
12х=9
х=12-9
х=3