DKXD $x \ge -1$
$pt\Leftrightarrow 25x^3+25 +\sqrt{25x^3+25}=4x^4+18x^2+20$$\Leftrightarrow 25x^3+25+\sqrt{25x^3+25}=(2x^2+4)^2+(2x^2+4)$
$\Leftrightarrow \sqrt{25x^3+25}=2x^2+4$
$\Leftrightarrow 25x^3+25=4x^4+16x^2+16$
$\Leftrightarrow (x^2-5x-3)(4x^2-5x+3)=0$