If a = 2, b = -3, then the value of 27a³ - 54a²b + 36ab² - 8b³ is?

$$\eqalign{ & a = 2,{\text{ }}b = - 3 \cr & {\text{So,}}27{a^3} - 54{a^2}b + 36a{b^2} - 8{b^3} \cr} $$
$$ = 27 \times {\left( 2 \right)^3} - 54 \times {\left( 2 \right)^2} \times \left( { - 3} \right) + $$       $$36 \times $$ $$\left( 2 \right) \times $$ $${\left( { - 3} \right)^2}$$ $$ -\, 8 \times $$ $${\left( { - 3} \right)^3}$$
$$\eqalign{ & = 27 \times 8 - 54 \times 4 \times - 3 + 36 \times 2 \times 9 - 8 \times - 27 \cr & = 216 + 216 + 648 + 648 \cr & = 1728 \cr} $$