Answer:
[tex]3 { x}^{2} (3 + x)[/tex]
Step-by-step explanation:
d) [tex]9 {x}^{2} + 3 {x}^{3} [/tex]
Take 3x^2 common from both the terms.
[tex] = > 3 {x}^{2} (3 + x)[/tex]