If 16, x, 9 are the first 3 terms of a geometric sequence, find the exact value of x
can someone tell me how to find it please :)
thanks

Question

anonymous · Answer

$${16 \over x}={x \over 9}$$

anonymous · Answer

$x=12$

anonymous · Answer

$x=-12$ is also a solution.

anonymous · Answer

16=4^2
9=3^2
x should be 3.5^2  = 12.25

anonymous · Answer

A geometric sequence is a sequence in which a term $a_i$ can be found by multiplying the previous term $a_{i-1}$ by some constant $d$. In our case d could be $-3/4$ or $3/4$.

anonymous · Answer

???
i got 3/4 too but thats wrong the right answer is 12 but i dont understand how they got it

why did you put it in a fraction???

anonymous · Answer

Yeah x is either $12$ or $-12$. You get it by solving the equation I put in my first comment.

anonymous · Answer

In a geometric sequence, the quotient of any two consecutive in the sequence must give the same value. So, in our case, $16/x =x/9$. Solve this equation for x and you will get the answer.

anonymous · Answer

thank you :)

anonymous · Answer

You're welcome :)