(x + 3y)(x² - 3xy + 9y²)
Solution:
[tex]x {}^{3} + (3y) {}^{3} \\ (x + 3y)(x {}^{2} - x \times 3y + 3 {}^{2} y {}^{2} ) \\ (x + 3y)(x {}^{2} - 3xy + 9y {}^{2} )[/tex]