Question

Which of the following options do not represent a prime factorization?

• A. 18 = $2\times 3\times 3$
• B. 25 = $5\times 5$
• C. 45 = $5\times 9$
• D. 50 = $2\times 5\times 5$

Answer 1

The correct option is C 45 = $5\times 9$

Prime factorization of a number is the product of factors of the number that are prime.
45 = $5\times \underset{–}{9}$
here, 9 is not a prime number so it is not a prime factorization of 45.