Question

explain why 7 ×11×13+13and 7 ×6 ×5×4×3×2×1+ 5 are composite number​

Answer 1

Answer:

7×11×13+13 = 13(7×11+1) 13 is common

= 13 ( 77+1)

=13(78)

therefore 13×2×3×13 where 78= 2×3×13.

therefore 7×11×13+13 can be expressed as product of prime no. hence it is composite.

7×6×5×4×3×2×1+5 = 5( 7×6×4×3×2×1+1)

= 5(1008+1)

= 5 × 1009

hence it is product of prime and hence it is composite.