# Question #b0d11

Mar 11, 2017

#### Answer:

$G C F = 13$

#### Explanation:

Write each term as the product of its prime factors, Then you know what you are dealing with.

$39 x = 3 \times 13 \times x$
$143 = \text{ } 13 \times 11$

The only factor they share is $13$ so this has to be the GCF.