Question

Show that 7×11×13+13 and 7×6×5×4are numbers

Answer 1

By definition, 

A composite number is a positive integer that has a factor other than 1 and itself. Now considering your numbers,

7×11×13+13 may be written as,  i.e. 13 * (78). So other than 1 and the number itself, 13 and 78 are also the factors of the number. Further, 78= 39 x 2. So, 39 and 2 are also it's factors. So this number is definitely not prime. Hence its composite number.

Similarly, 7×6×5×4×3×2×1+5 can be written as  , i.e. 5 * (1009). So, other than the number and 1, it have 5 and 1009 as it's factors too. So it is also a composite number.

Answer 2

AnSwer:

As we know that, a composite number is a positive integer that has a factor other than 1 and itself.

Now, Considering the given numbers,

• 7×11×13+13 can be written as,  l 13 × (78). So other than 1 and the number itself has other factors that are 13 and 78.

• Similarly , 78= 39 x 2. So, 39 and 2 are also it's factors.

━━━━━━━━━━━━━━━━━━━━━━━

Hence this number is a non prime number, that is, it is a composite number.

• Similarly, 7×6×5×4×3×2×1+5 can be written as, 5 × (1009).

So, other than the number and 1, it have 5 and 1009 as it's factors.

So, we can't say it as prime number.Hence, it is a composite number.

━━━━━━━━━━━━━━━━━━━━━━━