Answer:
x² + 6x + 9
Step-by-step explanation:
(x + 3)² = (x + 3)(x + 3)
Each term in the second factor is multiplied by each term in the first factor , that is
x(x + 3) + 3(x + 3) ← distribute parenthesis
= x² + 3x + 3x + 9 ← collect like terms
= x² + 6x + 9
