[tex]\huge \bf༆ Answer ༄[/tex]
Let's simply ~
[tex]{ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: - 5 {x}^{2} (4x - 6 {x}^{2} - 3)[/tex]
[tex]{ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:( - 5x {}^{2} \times 4x) - ( - 5 {x}^{2} \times 6 {x}^{2} ) - ( - 5 {x}^{2} \times 3)[/tex]
[tex]{ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: - 20 {x}^{3} - ( - 30 {x}^{4} ) - ( - 15 {x}^{2} )[/tex]
[tex]{ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: - 20 {x}^{3} + 30 {x}^{4} + 15 {x}^{2} [/tex]
[tex]{ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:30 {x}^{4} - 20 {x}^{3} + 15 {x}^{2} [/tex]