$(2x+1)(3x-2)=(5x-8)(2x+1)$
$\Leftrightarrow (2x+1)(3x-2)-(5x-8)(2x+1)=0$
$\Leftrightarrow (2x+1)(3x-2-2x-1)=0$
$\Leftrightarrow (2x+1)(x-3)=0$
$\Leftrightarrow \left[ \begin{array}{l}2x+1=0\\x-3=0\end{array} \right.$
$\Leftrightarrow \left[ \begin{array}{l}x=-\frac{1}{2}\\x=3\end{array} \right.$
$25-(x+3)^{2}=0$
$\Leftrightarrow 5^{2}-(x+3)^{2}=0$
$\Leftrightarrow [5-(x+3)](5+x+3)=0$
$\Leftrightarrow (2-x)(x+8)=0$
$\Leftrightarrow \left[ \begin{array}{l}2-x=0\\x+8=0\end{array} \right.$
$\Leftrightarrow \left[ \begin{array}{l}x=2\\x=-8\end{array} \right.$
