Find the 10th term in the following arithmetic sequence if the constant being added is -12: 20,8,-12,-16

Find the 10th term in the following arithmetic sequence if the constant being added is  -12

Step-by-step explanation:

20 - 12 = 8

8 - 12 = -4

-4 - 12 = -16

So the sequence will be

20; 8; -4; -16

an = 20 - 12(n - 1)

a10 = 20 - 12(10 - 1) = -88

where is the graph? need more info