a² - b² = (a - b)(a + b)
(x² - 16) / (3 - √(x + 5)) = (x - 4)(x + 4) (3 - √(x + 5) / (3 - √(x + 5) (3+- √(x + 5) = (x - 4)(x + 4) (3 - √(x + 5) / (9 - (x + 5) = (x + 4) (√(x + 5) - 3)
a² - b² = (a - b)(a + b)
(x² - 16) / (3 - √(x + 5)) = (x - 4)(x + 4) (3 - √(x + 5) / (3 - √(x + 5) (3+- √(x + 5) = (x - 4)(x + 4) (3 - √(x + 5) / (9 - (x + 5) = (x + 4) (√(x + 5) - 3)