19
19.5
To 4 decimal places, it is -1.7321 and 1.7321
8
In order to determine whether or not this is an arithmetic sequence, there must be at least 3 numbers.
8.75
19
19.5
5.15
8
41.25
8/2 = 4
0.2439
105
To 4 decimal places, it is -1.7321 and 1.7321
In order to determine whether or not this is an arithmetic sequence, there must be at least 3 numbers.
They are both equal; the value is 9.