Question

Question 6: Explain why 7 × 11 × 13 + 13 and 7 × 6 × 5 × 4 × 3 × 2 × 1 + 5 are composite numbers. Answer : Numbers are of two types - prime and composite. Prime numbers can be divided by 1 and only itself, whereas composite numbers have factors other than 1 and itself. It can be observed that 7 × 11 × 13 + 13 = 13 × (7 × 11 + 1) = 13 × (77 + 1) (how did or how do we reach this state? ) Do explain it..)

Answer 1

you r correct
if any number it has morethan two factors it is called a composite number
13×(77+1)=13×78=13×2×39(morethan two factors)
similarly
take 5 common
5(7×6*4*3*2*1+1)
=5*(1008+1)
=1*5*1009(morethan two factors)
so it is a composite number