Which of the following sequences represents an arithmetic sequence?

-7, -4, 1, 4,
2, -4, 8, -16,
1, 4, 9, 16,
-5, -3, -1, 1,

the formula for any geometric sequence is a n = a 1 · r n - 1 , where a n represents the value of the nth term, a 1 represents the value of the first term, r represents the common ratio, and n represents the term number. what is the formula for the geometric sequence 4, 8, 16, 32,

an = 32 · 2n - 1
an = 2 · 4n - 1
an = 4 · ()n - 1
an = 4 · 2n - 1

what is the value of the 8th term of the sequence 4, 8, 16, 32,

1,024
512
128
2,048

which of the following questions describes the equation = -20?

what number, when multiplied by four, is equal to negative twenty?
what number, when divided by negative four, is equal to twenty?
what number, when multiplied by negative twenty, is equal to four?
what number, when divided by four, is equal to negative twenty?