Question

. What is the prime factorization of 56?

Answer 1

Here's a list of prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53

Take the first one, divided your number by it as many times as possible. Then try the next, and the next...you can stop when the number you are trying as a divisor is greater than the square root of the number you are trying to divide.

So as an example, let's try 75:

75 is not divisible by 2
75 is divisible by 3, 75/3 = 25
25 is not divisible by 3
25 is divisible by 5, 25/5 = 5
5 is divisible by 5, 5/5 = 1
time to stop. prime factorization was 3*5*5

Answer 2

Looking at your answer choices there, it should be clear that all but one of them involve factors which can be divided by other numbers, and are thus not prime.