Answer:
x² + 8x + 15
Step-by-step explanation:
given
(x + 3)(x + 5)
each term in the second factor is multiplied by eac term in the first factor, that is
x(x + 5) + 3(x + 5) ← distribute parenthesis
= x² + 5x + 3x + 15 ← collect like terms
= x² + 8x + 15