The value of P 4 6 + 4 · P 3 6 is ______.

Step-by-step solution

Formula for P r n = n ! n - r ! P 4 6 + 4 . P 3 6 = 6 ! 2 ! + 4 × 6 ! 3 ! = 6 × 5 × 4 × 3 × 2 × 1 2 × 1 + 4 × 6 × 5 × 4 × 3 × 2 × 1 3 × 2 × 1 = 360 + 4 × 120 = 360 + 480 = 840