Let's solve each equation separately:

1) $7x-24$/12 + 26 = 31
$7x-24$/12 = 31 - 26
$7x-24$/12 = 5
7x - 24 = 60
7x = 84
x = 12

2) 144 - $x/11+21$ * 5 = 14
144 - 5$x/11+21$ = 14
144 - 5x/11 - 105 = 14
39 - 5x/11 = 14
5x/11 = 25
5x = 275
x = 55

3) $105-(25+6x)<em>4$ 30 = 150
$105-(25+6x)<em>4$ = 5
$105-(25+6x)</em>4$ = 5/30
$105-4(25+6x)$ = 1/6
105 - 100 - 24x = 1/6
5 - 24x = 1/6
-24x = 1/6 - 5
-24x = -29/6
x = 29/$6\ast 24$ x = 29/144

Therefore, x = 12, 55, 29/144.