$\frac{2x -1}{2015} } + \frac{2x +1}{2013} + \frac{2x-3}{2017} = \frac{x}{2007} - 2$
⇔ $\frac{2x -1}{2015} + \frac{2x +1}{2013} + \frac{2x-3}{2017} +3 = \frac{x}{1007} - 2+3$
⇔ $(\frac{2x -1}{2015}+1) + (\frac{2x +1}{2013}+1) + (\frac{2x-3}{2017}+1) = \frac{x}{1007} + 1$
⇔ $\frac{2x+2014}{2015} + \frac{2x+2014}{2013}+\frac{2x+2014}{2017} = \frac{x+1007}{1007}$
⇔ $(2x + 2014)(\frac{1}{2015} + \frac{1}{2013}+\frac{1}{2017}) = \frac{x+1007}{1007}$
⇔ $2(x + 1007)(\frac{1}{2015} + \frac{1}{2013}+\frac{1}{2017}) - (x+1007)\frac{1}{1007}= 0$
⇔ $2( x + 1007)(\frac{1}{2015} + \frac{1}{2013}+\frac{1}{2017}-\frac{1}{1007}) = 0$
Vì $\frac{1}{2015} + \frac{1}{2013}+\frac{1}{2017}-\frac{1}{1007}$ $khác$ $0$
$và$ $2$ $khác$ $0$ ⇔ x + 1007 = 0 ⇔ x = -1007
S = { -1007 }
