Question

One number has a prime factorization of 2 3 • 3 2, and another number has a prime factorization of 2 2 • 3 3. Which of the following expressions would equal the greatest common factor of these two numbers?



2 5 • 3 5


2 3 • 3 3


2 2 • 3 2


2 • 3

Answer 1

The greatest common factor is the largest number that will go into both of them now
2^2 and 3^2 go into both numbers. You take the highest number of twos that go into both and the highest number of threes and multiply them together.

The normal question is to give you two number and work out the HCF (highest common factor)
You would then break both numbers down into their prime factors and then get to the position you were in. In other words, this question has been made easier by giving you the factorisation. I suspect you haven't been asked the question this way before. But in fact this is much easier. (((((((( 2^2 , 3^2 )))))))) or 2*2 , 3*2. (C)