Question

Why is (a+b)(a-b) = a2-b2

Answer 1

see explanation

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