Arithmetic and Geometric Sequences

Which sequence is an arithmetic sequence?

• 3, 6, 2, 7, ...

• 3, 6, 12, 24, ...

• 3, 6, 10, 15, ...

• 3, 7, 11, 15, ...

This is an arithmetic sequence. 5, 2, –1, –4, . . .

What is a₇ ?

• -13

• -11

• -18

• -22

In a certain arithmetic sequence, a₅ = 12 and a₆ = 16. What is a₁ ?

• -8

• -4

• 4

• 8

The first term of an arithmetic sequence is b and the second term is c. What is the explicit formula to find the n^th term of the sequence?

• a_n = b + (n − 1) c

• a_n = c + (n − 1) b

• a_n = b + (n − 1) (b − c)

• a_n = b + (n − 1) (c − b)

• Arithmetic

• Geometric

Answer explanation

Percentages are almost always Geometric.

• Arithmetic

• Geometric

Answer explanation

Percentages are almost always Geometric.

• 315

• 330

• 345

• 360

The explicit formula for a sequence is a_n = 5 − 3n. What is the value of a₂₂ ?

• a₂₂ = -61

• a₂₂ = 61

• a₂₂ = -1

• a₂₂ = -51

In an arithmetic sequence, the third term is 1 and the ninth is 49. What is the explicit formula for the sequence?

• a_n = 8n − 15

• a_n = −8n − 15

• a_n = 8n − 23

• a_n = −8n − 23

What function describes the sequence?

• f (x) = −0.7x + 8

• f (x) = −0.7x + 8.7

• f (x) = 0.7x + 8

• f (x) = 0.7x + 8.7