Question

Show that
2*5*13*43+13*41 is a composite no

Answer 1

2 x 5 x 13 x 43 + 13 x 41 is composite because we can group those number into a non-prime number.

These are the steps:

2 x 5 x 13 x 43 + 13 x 41

13 x (2 x 5 x 43 + 41)

Since composite is not prime, and we know (by factor) that the number above is not prime, therefore the number is composite.