Geometric Sequences

What is the common ratio for the sequence:
28, 14, 7, 3.5...

• 2
• 1/2
• -14
• -7

Find the common ratio: 4, -16, 64, -256, ...

• r = -4
• r = 2
• r = -2
• r = 4

Find the next three terms: 4, 12, 36, 108, ...

• 324, 972, 2916
• 972, 2916, 8748
• 405, 1215, 3645

Write an explicit rule for the general term of the sequence 5, 15, 45, . . . ?

• a_n = a_n-1 x 3
• a_n = 5(3)^n-1
• a_n = 3(5)^n-1
• a_n = 5 + (n-1)3

Find the 11^th term for:  64, -32, 16, -8, …  

• -.0625
• .0625
• -.03125
• .03125

Which sequence is represented by the equation 2(7)^n-1 ?

• 7, 14, 28, 56...
• 2, 14, 98, 686...
• 2, 9, 16, 23...
• 7,9,11,13...

This image shows how a certain bacteria grows in a petri dish. What is the common ratio of this sequence?

• 4
• 3
• 2
• 6

What is the 14th term of the geometric sequence?

• 14,348,907
• 4,782,969
• 1,594,323
• 45

Given the sequence:

125, 25, 5, ....

Write the rule a_n using the geometric sequence formula:

• a_n = (125)(1/5)^(n-1)

• a_n = 625(1/5)^(n-1)

• a_n = 625(5)^(n-1)

• a_n = 125 + 5n

Does this graph show an arithmetic or a geometric sequence?

• Arithmetic
• Geometric
• Neither
• Both