c³ + 5 - (c² - 20 + 4)(c + 2) =
c³ + 5 - (c² - 16)(c + 2) =
c³ + 5 - (c³ + 2c² - 16c - 32) =
c³ + 5 - c³ - 2c² + 16c + 32 =
16c - 2c² + 37