Answer:
x² + 6x + 9
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 ← in standard form