Question 144227
select the next number in the series:
{{{298}}}{{{ 209}}}{{{ 129}}}{{{ 58}}}{{{ -4 }}}{{{...}}}

let's find a pathern:

{{{298- 209=89}}}……..

{{{129 -58 =71}}}……… 

{{{58-( -4)=62}}}….

The difference between {{{89}}} and {{{71}}} is {{{2*9=18}}}, the difference between {{{71}}} and {{{62}}} is {{{1*9=9}}},the difference between {{{-4}}} and next number {{{x}}} will be also {{{1*9=9}}} less than {{{62}}}, so we can write an equation like this:

{{{-4-(x)=62-9}}}….

{{{-4-(x)=53}}}….

{{{-x=53+4}}}….

{{{-x=57}}}….

{{{x = -57}}}…….your {{{answer}}} 

{{{298}}}{{{ 209}}}{{{ 129}}}{{{ 58}}}{{{ -4 }}}{{{-57}}}