Foil Method

How do you multiply:
(x + 11)(x – 11)

Use the foil method:
(x + 11)(x - 11)
= x(x) + x(-11) + 11(x) + 11(-11) {used foil method}
= x2- 11x + 11x - 121 {multiplied through}
= x2- 121 {combined like terms}

- Algebra House