$(2x+5)^2=(3x-1)^2$
⇔ $(2x+5)^2-(3x-1)^2=0$
⇔ $(2x+5+3x-1)(2x+5-3x+1)=0$
⇔ $(5x+4)(-x+6)=0$
⇔ \(\left[ \begin{array}{l}5x+4=0\\-x+6=0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}5x=-4\\-x=-6\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=\frac{-4}{5}\\x=6\end{array} \right.\)
Vậy $S=${$\frac{-4}{5};6$}