Simplify:

$3a \times [8b ÷ 4 - 6{a - (5a - \overline{3b - 2a})}]$

$3a \times [8b ÷ 4 - 6{a - (5a - \overline{3b - 2a})}]$

= $3a \times [8b ÷ 4 - 6{a - (5a - 3b + 2a)}]$

= $3a \times [8b ÷ 4 - 6{a - (5a + 2a - 3b )}]$

= $3a \times [8b ÷ 4 - 6{a - (7a - 3b )}]$

= $3a \times [8b ÷ 4 - 6{a - 7a + 3b }]$

= $3a \times [8b ÷ 4 - 6{-6a + 3b }]$

= $3a \times [8b ÷ 4 + 36a - 18b ]$

= $3a \times [2b + 36a - 18b]$

= $3a \times [2b - 18b + 36a]$

= $3a \times [-16b + 36a]$

= $-48ab + 108a^2$

Hence, $3a \times [8b ÷ 4 - 6{a - (5a - \overline{3b - 2a})}] = 108a^2 - 48ab$