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The given number is: $ 15 \times 7 + 7 $

There are two terms in the given number and $ 7 $is a common factor.

We take $ 7 $as common, then we have

$ 15 \times 7 + 7 = 7\left( {15 \times 1 + 1} \right) $

$ 15 \times 7 + 7 = 7\left( {15 + 1} \right) $

$ 15 \times 7 + 7 = 7\left( {16} \right) $

$ 15 \times 7 + 7 = 112 $

When we factorize\[112\], we will get

$ 112 = 2 \times 2 \times 2 \times 2 \times 7 $

$ 112 = {2^4} \times 7 $

This number is divisible by $ 2,4,7,8 $and $ 16 $, which means that it has more than two factors.

Therefore, $ 15 \times 7 + 7 $ is a composite number

Additional information: the divisibility rule is given below:

(i) Divisibility rule of $ 2 $: Which states that for a number to be divisible by $ 2 $, the unit digit must have \[0,2,4,6\]or \[8\] in units place.

(ii) Divisibility rule of $ 4 $: Which states that for a number to be divisible by $ 4 $, the unit and tens digit should be divisible by $ 4 $

(iii) Divisibility rule of $ 7 $: We need to double the last digit of the number and then subtract it from the remaining number. If the result is divisible by $ 7 $, then the original number will also be divisible by $ 7 $.

(i) Natural number: \[1,2,3,4,\]------

(ii) Whole number:\[\;0,1,2,3,4,\] ------

(iii) Integers: \[ - 4, - 3, - 2, - 1,0,1,2,3,4,\]-----

(iv) Positive integers: \[1,2,3,\]-----

(v) Negative integers: \[ - 4, - 3, - 2, - 1\]