7x-(3+2x)=x+9;
7х - 3 - 2х = х + 9
7х - 2х - х = 9 + 3
4х = 12
х = 12÷4 = 3
13-(2x-5)=x-3;
13 - 2х + 5 = х - 3
13 + 5 + 3 = х + 2х
21 = 3х
х = 21÷3 = 7
3x-(10-9x)=22x;
3х - 10 + 9х = 22х
- 10 = 22х - 3х - 9х
- 10 = 10х
х = - 10÷10 = - 1
26-(17-2x)=5x.
26 - 17 + 2х = 5х
26 - 17 = 5х - 2х
9 = 3х
х = 9÷3 = 3