Verified answer

a) x² - 14x + 33 = (x² - 14x + 49) - 16 = (x - 7)² - 16

b) (x - 7)² - 16 = (x - 7)² - 4² = (x - 7 - 4)(x - 7 + 4) = (x - 11)(x - 3)