Answer:
see explanation
Step-by-step explanation:
(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 parenthesis
= a² - ab + ab - b² ← collect like terms
= a² - b²
This is a standard algebraic identity, called the difference of squares
