Question

Write out the prime factor of the following numbers. a. 15 b. 21 c. 38 d. 42

Answer 1

A: 5 and 3

B: 7 and 3

C: 19 and 2

D: 2 and 3 and 7

Answer 2

Answer with explanation:

We know that the prime factorization of a number "n" is given by:

$n=p_1\cdot p_2\cdot p_3\cdot p_4$

where $p_i's$ are distinct prime.

(a)

$15$

It could be written as:

$15=3\times 5$

Hence, the prime factors of this number are:

3 and 5.

(b)

21

It could be written as:

$21=3\times 7$

Hence, the prime factors of this number are:

3 and 7.

(c)

38

It could be written as:

$38=2\times 19$

Hence, the prime factors of this number are:

2 and 19.

(d)

42

It could be written as:

$42=2\times 3\times 7$

Hence, the prime factors of this number are:

2 , 3 and 7.