What is the 8th term of the geometric sequence where a1 = 625 and a3 = 25

Question

anonymous · Answer

well you know that the first term is 625 so find the difference by finding out what 625 +x = 25

then you know the difference. then you plug that into the equations that should have been provided for you

asnaseer · Answer

this is virtually identical to your previous question: http://openstudy.com/updates/4fc29732e4b0964abc83e4db use the same methods explained to you there to find the answer.

anonymous · Answer

Again, utilize the formula $a_n=a_1 C^{n-1}$ to find out what $C$ is for your sequence.

anonymous · Answer

that formula confuses me

anonymous · Answer

What is confusing you about it?  Every time you add $1$ to $n$, you are increasing the term by a power of $C$, which is what you want.  $C$ is the common ratio.

asnaseer · Answer

I would then suggest you use this site to first learn a bit more about these types of sequences: http://www.mathsisfun.com/algebra/sequences-sums-geometric.html

anonymous · Answer

try to solve yourself