If (1 × 2 × 3 × 4 ........ × N) = N!, Then 15! - 14! - 13! Is Equ

1.	If (1 × 2 × 3 × 4 ........ × N) = N!, Then 15! - 14! - 13! Is Equal To ___?
Answer» 15! - 14! - 13! = (15 × 14 × 13!) - (14 × 13!) - (13!) = 13! (15 × 14 - 14 - 1) = 13! (15 × 14 - 15) = 13! X 15 (14 - 1) = 15 × 13 × 13!. 15! - 14! - 13! = (15 × 14 × 13!) - (14 × 13!) - (13!) = 13! (15 × 14 - 14 - 1) = 13! (15 × 14 - 15) = 13! x 15 (14 - 1) = 15 × 13 × 13!.

If (1 × 2 × 3 × 4 ........ × N) = N!, Then 15! - 14! - 13! Is Equal To ___?

Answer»

15! - 14! - 13!

= (15 × 14 × 13!) - (14 × 13!) - (13!)

= 13! (15 × 14 - 14 - 1)

= 13! (15 × 14 - 15)

= 13! X 15 (14 - 1)

= 15 × 13 × 13!.

15! - 14! - 13!

= (15 × 14 × 13!) - (14 × 13!) - (13!)

= 13! (15 × 14 - 14 - 1)

= 13! (15 × 14 - 15)

= 13! x 15 (14 - 1)

= 15 × 13 × 13!.