Thread: so confusing!

hello! I am new! I can post any math homework question I have right?
if this is the case I have one that I don't understand at all!
determine two geometreic sequences whose first terms are 18x-9, 2x+8 and x-1 how would I go about and do this question?

thanks for your help! in advance!

Originally Posted by george93

hello! I am new! I can post any math homework question I have right?
if this is the case I have one that I don't understand at all!
determine two geometreic sequences whose first terms are 18x-9, 2x+8 and x-1 how would I go about and do this question?

thanks for your help! in advance!

I presume you are looking for two values of x that would suit?

<-- This defines .

<-- This defines r.

So

<-- This defines x.

So solve for x:








Frankly I wouldn't try to fiddle with factoring it, I'd just use the quadratic formula, but as it happens it DOES factor: (which I figured out by using the qf. )


So x = 5 or x = -11/14.

So your two sequences are:
x = 5: 81, 18, 4, ...
x = -11/14: -324/14, 90/7, -25/14, ...

-Dan