Answer:
1x also written as: x
Explanation:
The GCF is the number/variable that both terms have in common. Here, the only number that can go into 3 and 4 is 1. For variables, 4 has only one x and 3 has 2 x's. But the GCF will still only be 1 x because only 1 can go into both. So the answer is 1x, or just x.