*Answer**
To get the Greates Common Factor (GCF) of 1700 and 1938 we need to factor each value first and then we choose all the copies of factors and multiply them:
1700: 2 2 5 5 17
1938: 2 3 17 19
GCF: 2 17
The Greates Common Factor (GCF) is: 2 x 17 = 34