[tex]\bf \begin{array}{lclclcllll}
125&,&-50&,&20&,&-8\\
&\frac{-50}{125}=-\frac{2}{5}&&\frac{20}{-50}=-\frac{2}{5}&&\frac{-8}{20}=-\frac{2}{5}
\end{array}[/tex]
so.. notice, if you divide a term by the term before it, you end up with a quotient of -2/5
that means, to get from one number to the next, you simply multiply that number by some value, in this case -2/5, it cold be anything, that common multiplier is called the "common ratio"
and lists like this one, are "geometric sequences"
