Answer:
[tex] - 27 {x}^{3} y - 63 {x}^{2} z[/tex]
Step-by-step explanation:
[tex]9x( - 3 {x}^{2} y - 7xz)[/tex]
[tex] = 9x \times ( - 3 {x}^{2} y) + 9x \times ( - 7xz)[/tex]
[tex] = - 27 {x}^{3} y - 63 {x}^{2} z[/tex]
