What are the steps to this problem (and the answer?)

Answer:
[tex](25 {x}^{2} + 20xy + 16 {x}^{2} )(5x - 4y) = \\ 125 {x}^{3} + 100 {x}^{2} y + 80x {y}^{2} - 100 {x}^{2} y \\ - 80x {y}^{2} - 64 {y}^{3} = \\ 125 {x}^{3} - 64 {y}^{3} \\ please \: give \: brainliest[/tex]