x² - a² = ()(x + a)

x² - 2ax + a² = (x - a)(x + a)

x³ + a³ = (x + a)(x² - ax + a²)

(a + b) ⋅ c = a ⋅ c + b ⋅ c

x² - a² = (x - a)(x + a)
is a difference of two squares