Question

What is the GCF of 8x3y2 + 20x2y4?

Answer 1

First, add the two together. 

8x3y2+20x2y4=28x5y6

The GCF is 1, because 5 is a prime number that isn't divisible by anything but 1.

GCF=1

Answer 2

8x^3y^2 = 4x^2y^2 (2x)
20x^2y^4 = 4x^2y^2 (5y^2)

GCF = 4x^2y^2