3 × х + 1200 = 9000
3 × х = 7800
х = 7800 : 3
х = 2600
3х+1200=9000
3х=9000-1200
3х=7800
х=7800:3
х=2600
3 × х + 1200 = 9000
3 × х = 7800
х = 7800 : 3
х = 2600
3х+1200=9000
3х=9000-1200
3х=7800
х=7800:3
х=2600