Answer:
Geometric Sequence
Step-by-step explanation:
1. Check the difference.
The difference between the 1st and 2nd term

The difference between the 2nd and 3rd term

The difference is not the same. Therefore, it is not an arithmetic sequence.
2. Check the ratio
The ratio between the 1st and 2nd term

The ratio between the 2nd and 3rd term

The ratio is the same. Therefore, it is a geometric sequence.
Answer:
8
Step-by-step explanation:
18-12
12-X
X=12*12/18
X=8mm
I'm not 100% sure, but I believe the answer is A. x²-5/4x+1