Answer:
49x³ + 84x² + 62x + 45
Step-by-step explanation:
given
(7x + 9)(7x² + 3x + 5)
Each term in the second factor is multiplied by each term in the first factor, that is
7x(7x² + 3x + 5) + 9(7x² + 3x + 5) ← distribute parenthesis
= 49x³ + 21x² + 35x + 63x² + 27x + 45 ← collect like terms
= 49x³ + (21x² + 63x² ) + (35x + 27x ) + 45
= 49x³ + 84x² + 62x + 45