Answer:
2y
Explanation:
To find the GCF ( Greatest Common factor), for an algebraic expression like the one given, all you have to do if look over the expression and circle all the terms they both share, in this case, both 4yz and 2y^2 had 2y in them, except in different forms.
If you find it difficult to recognize the similarities, divide the expressions as much as you can.
Hope this helps