Question

\(\frac{x-7}{2005}\)+\(\frac{x-6}{2006}\)=\(\frac{x-5}{2007}\)+\(\frac{x-4}{2008}\)

Answer 1

\(\left(\frac{x-7}{2005}-1\right)+\left(\frac{x-6}{2006}-1\right)=\left(\frac{x-5}{2007}-1\right)+\left(\frac{x-4}{2008}-1\right)\)

\(\Leftrightarrow\frac{x-2012}{2005}+\frac{x-2012}{2006}=\frac{x-2012}{2007}+\frac{x-2012}{2008}\)

\(\Leftrightarrow\frac{x-2012}{2005}+\frac{x-2012}{2006}-\frac{x-2012}{2007}-\frac{x-2012}{2008}=0\)

\(\left(x-2012\right).\left(\frac{1}{2005}+\frac{1}{2006}-\frac{1}{2007}-\frac{1}{2008}\right)=0\)

\(\text{vì }\left(\frac{1}{2005}+\frac{1}{2006}-\frac{1}{2007}-\frac{1}{2008}\right)\ne0\Rightarrow x-2012=0\Rightarrow x-2012\)