Answer:
a² + 2ab + b²
Step-by-step explanation:
Given
(a + b)²
= (a + b)(a + b)
Each term in the second factor is multiplied by each term in the first factor, that is
a(a + b) + b(a + b) ← distribute both parenthesis
= a² + ab + ab + b² ← collect like terms
= a² + 2ab + b²