What is the gcf of the terms in 4a^4+6a^2?

The GCF means Greatest common factor.
In this case it would be the biggest number that goes into 4 and 6 which is 2.

The first half of you answer is 2

The second half means the most amount of a’s that can go into the biggest number of a’s (doesn’t multiply)
Example:
a^4 means there are 4 a’s multiplying
a^2 means there are 2 a’s multiplying
a*a*a*a
a*a
Going back to the most amount a’s going into the biggest number of a’s means that in this equation the most amount of a’s that go into the biggest number of a’s is a^2.

Your answer is 2a^2

The answer would be c.8(2)=16-16=0 -8(2)=16-16=0