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, ...

• 36, -108, 324
• -324, -972, -2916
• 324, -972, 2916
• -108, 324, -972

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

Write the explicit formula for the following geometric sequence:

10, 20, 40, 80, ...

• a_n = 10(2)^n-1

• a_n = 2(10)^n-1

• a_n = 10(2)ⁿ

• a_n = 2(10)ⁿ

Find the first four terms of the sequence given the rule:
a_n = 4(5)^n-1

• 20, 100, 500, 2500
• 5, 20, 80, 320
• 4, 20, 100, 500
• 4, 9, 14, 19

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...

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

• -.0625
• .0625
• -.03125
• .03125

Find a₁₂ in the sequence -1, -3, -9, -27, ...

• -177,147
• -19,683
• -59,049
• 118,098

Find a₁₂ for the geometric sequence defined by the following formula:

a_n = 6(2)^n-1

• 4096

• 24,576

• 2048

• 12,288