The product of the sum of a and b and their difference.

Step-by-step explanation:

The product of the sum of a and b and their difference:

(a + b) (a - b) = a² - b²

Proof:

L = (a + b) (a - b) use FOIL

L = (a) (a) + (a) (-b) + (b) (a) + (b) (-b)

L = a² - ab + ab - b² combine like terms

L = a² - b² + (-ab + ab)

L = a² - b²

R = a² - b²

L = R