1. Are the following sequences arithmetic or geometric? If they are arithmetic, state the value of d. If
they are geometric, state r.
n 1 2 3 4
f(n) 6 12 18 24

Type of Sequence:
Common difference (d) or ratio (r):

n 1 2 3 4
f(n) 2 14 98 686

Type of Sequence:
Common difference (d) or ratio (r):

n 1 2 3 4
f(n) 160 80 40 20

Type of Sequence:
Common difference (d) or ratio (r):

n 1 2 3 4
f(n) -40 -25 -10 5

Type of Sequence:
Common difference (d) or ratio (r):

n 1 2 3 4
f(n) 7 -21 63 -189

Type of Sequence:
Common difference (d) or ratio (r):

2. For the following arithmetic sequences, state the explicit formula. Find t7 andt20.
- 10, - 4, 2, 8, 14, ... Explicit Formula:

t7:
t20:

10, 8, 6, 4, ... Explicit Formula:

t7:
t20:

36, 31, 26, 21, ... Explicit Formula:

t7:
t20:

3. For the following geometric sequences, state the explicit formula. Find t4 andt12.
1, 3, 9, 27, ... Explicit Formula:

t4:
t12:

12, 6, 3, 1.5, ... Explicit Formula:

t4:
t12:

9, -3, 1, ... Explicit Formula: