Simplify:

$3x - [4x - \overline{3x - 5y} - 3{2x - (3x - \overline{2x - 3y})}]$

$3x - [4x - \overline{3x - 5y} - 3{2x - (3x - \overline{2x - 3y})}]$

= $3x - [4x - \overline{3x - 5y} - 3{2x - (3x - 2x + 3y)}]$

= $3x - [4x - \overline{3x - 5y} - 3{2x - (x + 3y)}]$

= $3x - [4x - \overline{3x - 5y} - 3{2x - x - 3y}]$

= $3x - [4x - \overline{3x - 5y} - 3{x - 3y}]$

= $3x - [4x - \overline{3x - 5y} - 3x + 9y]$

= $3x - [4x - 3x + 5y - 3x + 9y]$

= $3x - [(4x - 3x - 3x) + (5y + 9y)]$

= $3x - [-2x + 14y]$

= $3x + 2x - 14y$

= $5x - 14y$

Hence, $3x - [4x - \overline{3x - 5y} - 3{2x - (3x - \overline{2x - 3y})}] = 5x - 14y$