Explain why 7 x 11 x 13 + 13 and 7 x 6 x 5 x 4 x 3 x 2 x 1 + 5

 7 x 11 x 13 + 13  =13(77+1)=13x78 product of two numbers.

 7 x 6 x 5 x 4 x 3 x 2 x 1 + 5 =5(42x24+1) product of two numbers.

Since both the numbers can be expressed as the product of two numbers other then 1 and themselves so they are composite