$3\sqrt{x - 1} + \sqrt{9x -9} - \sqrt{25x - 5} + 2\sqrt{4x - 4} = 24$
$ĐK:\, x \geq 1$
$(*) 3\sqrt{x - 1} + \sqrt{9(x -1)} - \sqrt{25(x - 1)} + 2\sqrt{4(x - 1)} = 24$
$\Leftrightarrow 3\sqrt{x - 1} + 3\sqrt{x - 1} - 5\sqrt{x - 1} + 4\sqrt{x - 1} = 24$
$\Leftrightarrow 5\sqrt{x - 1} = 24$
$\Leftrightarrow \sqrt{x - 1} = \dfrac{24}{5}$
$\Rightarrow x - 1 = \dfrac{576}{25}$
$\Rightarrow x = \dfrac{601}{25}$
