Answer:
2x^2y^4
Explanation:
If you cant mentally determine the common factor between the numbers, you can always list each numbers factors and determine the greatest common factor.
10: 1, 2, 5, 10
16: 1, 2, 4, 8, 16
14: 1, 2, 7, 14
as you can see, 2 is the only common factor between the numbers. As for the variables, always look at the variable with the smallest exponent, this is your common variable.