\(\frac{x+140}{x+260}=71+65\times4\)
\(\Rightarrow\frac{x+260-120}{x+260}=331\)
\(\Rightarrow1-\frac{120}{x+260}=331\)
\(\Rightarrow\frac{120}{x+260}=-330\)
\(\Rightarrow x+260=\frac{120}{-330}\)
\(\Rightarrow x+260=\frac{-4}{11}\)
\(\Rightarrow x=\frac{-4}{11}-260=-\frac{4}{11}-\frac{2860}{11}=\frac{-2864}{11}\)
\(\frac{x+140}{x+260}=71+65.4\)
<=> \(\frac{x+140}{x-260}=331\)
<=> \(\frac{x+140}{x-260}=\frac{331x-86060}{x-260}\)
,<=> \(x+140=331x-86060\)
<=> \(-330x=-86200\)
<=> \(x=\frac{8620}{33}\)