c² - 100We're asked to simplify the following expression:→ (c - 10)(c + 10)Apply the FOIL method to simplify this.Recall that FOIL stands for: → first, outside, inside, lastMultiply the first terms:→ c*c = c²Multiply the outside terms:→ c * 10 = 10cMultiply the inside terms:→ -10*c = -10cMultiply the last terms:→ -10*10 = -100Add all the terms:⇒ c² + 10c - 10c - 100Simplify the middle:⇒ c² - 100