A prime factor is a factor of a whole number that is a prime number.
What are the prime factors of 18 and 84 ?
The factors of 18 are 1, 2, 3, 6, 9, and 18. Of these numbers, 2 and 3 are prime numbers.
Therefore, the prime factors of 18 are 2 and 3.
The factors of 84 are 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, and 84. Of these numbers, 2, 3, and 7 are prime numbers.
Therefore, the prime factors of 84 are 2, 3, and 7.