Chapter 6 - Section 6.1 - The Greatest Common Factor and Factoring by Grouping - Exercise Set - Page 427: 10

$x^2$

The $GCF$ of $ 1,3, $ and $ 6 $ is $ 1 .$ The $GCF$ of $ x^2,x^3, $ and $ x^2 $ is $ x^2 .$ Hence, the $GCF$ of the given expressions, $ x^2y,3x^3y \text{ and } 6x^2 ,$ is \begin{array}{l}\require{cancel} 1x^2 \\\\= x^2 .\end{array}