15 - { 18 - [ (2 x x - 8 ) :3-5 ] :3+12 } :9 +2 = 14
15 - { 18 - [( 2xx - 8):3-5] +12 } :9 = 14-2
{18 - [ (2 x x - 8 ) :3-5 ] :3+12 } :9 = 15 - 12
18 - [ (2 x x - 8 ) :3-5 ] :3+12 = 3x 9
18 - [ (2 x x - 8 ) :3-5 ] :3 = 27 -12
[ (2 x x - 8 ) :3-5 ] :3 = 18 - 15
(2 x x - 8 ) :3-5 = 3x3
( 2xx -8 ) : 3 = 9+5
2xx- 8 = 14x3
2xx - 8 = 42
2x = 42-8
2x=34
x=34:2
x=17