SOLUTION: The first term of a geometric sequence is 9 and the third term is 4. Find the possible values for the second and fourth terms.

Question 842089: The first term of a geometric sequence is 9 and the third term is 4. Find the possible values for the second and fourth terms.
Answer by fcabanski(1391) (Show Source): You can put this solution on YOUR website!
A geometric sequence is a sequence in which a common factor multiplies each term to get to the next.

9x = y

yx = 4

Solve the two equations for x and y.

Substitute 9x for y in the second equation.

9x*x = 4

x = + or - = + or - 2/3. Either one works. I'll show -2/3. You can try 2/3 on your own.

9 * -2/3 = 18/3 = -6

-6 * -2/3 = 12/3 = 4

4 * -2/3 = -8/3

Possible sequence: 9, -6, 4, -8/3

RELATED QUESTIONS
the first and second terms of a geometric sequence is 108 and the sum of the third and... (answered by josgarithmetic)

The first term of a geometric progression is 75 and the third term is 27.Find the two... (answered by ikleyn)