Cộng 2 vế với 2 ta có :
5-x^2/2012 + 1 = (4-x^2/2013+1) - (x^2-3/2014-1)
<=> 2017-x^2/2012 = 2017-x^2/2013 - x^2-2017/2014 = 2017-x^2/2013+ 2017-x^2/2014
<=> 2017-x^2/2013 + 2017-x^2/2014 - 2017-x^2/2012 = 0
<=> (2017-x^2).(1/2013+1/2014-1/2012) = 0
<=> 2017-x^2 = 0 ( vì 1/2013+1/2014-1/2012 khác 0 )
<=> x = \(\sqrt{2017}\)
k mk nha
\(\Leftrightarrow\frac{5-x^2}{2012}+1=\frac{4-x^2}{2013}+1+\frac{3-x^2}{2014}+1\)
\(\Leftrightarrow\frac{2017-x^2}{2012}-\frac{2017-x^2}{2013}-\frac{2017-x^2}{2014}=0\)
\(\Leftrightarrow\left(2017-x^2\right)\left(\frac{1}{2012}-\frac{1}{2013}-\frac{1}{2014}\right)=0\)
\(\Leftrightarrow2017-x^2=0\)
\(\Leftrightarrow x^2=2017\)
\(\Leftrightarrow x=\sqrt{2017}\)
V...\(S=\left\{\sqrt{2017}\right\}\)
