Answer:
a² + 4ab + 4b²
Step-by-step explanation:
Given
(a + 2b)²
= (a + 2b)(a + 2b)
Each term in the second factor is multiplied by each term in the first factor, that is
a(a + 2b) + 2b(a + 2b) ← distribute both parenthesis
= a² + 2ab + 2ab + 4b² ← collect like terms
= a² + 4ab + 4b²
