# How do you find the greatest common factor of 105x, 30yx, 75x?

Dec 1, 2016

15

#### Explanation:

Remember that the greatest common factor (GCF) is the largest factor that each number has in common.

First, you split each one up into simplest form.
$105 x = 3 \cdot 5 \cdot 7 \cdot x$
$30 x y = 2 \cdot 3 \cdot 5 \cdot x \cdot y$
$75 x = 3 \cdot 5 \cdot 5$

Then you pick the common factor(s) from each one. Basically, what does each one have in common. We see that each one has a 3 and a 5. Thus the GCF is $3 \cdot 5 = 15$