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