Question

a(9a^2+6a)-4a(9a^2-2a)

Answer 1

9a³+6a²-36a³+8a²= 14a²-27a³

Answer 2

$a(9 {a}^{2} +6a)-4a(9a^2-2a) = \\ = 9 {a}^{3} + 6 {a}^{2} - 36 {a}^{3} + 8 {a}^{2} = \\ = 14 {a}^{2} - 27 {a}^{3} .$