9) 4х – 6 = 2х + 12 10) 3х + 3 = 2х + 13 11) 9 – 3х = 20 – 4х
9) 4х-6=2х+12
4х-2х=6+12
2х=18
х=18/2
х=9
10) 3х+3=2х+13
3х-2х=13-3
х=10
11) 9-3х=20-4х
4х-3х=20-9
х=11