$Đk:x\ge0;x\ne25$
$A=\bigg(\dfrac{2}{\sqrt{x}+5}-\dfrac{15-\sqrt{x}}{25-x}\bigg):\dfrac{\sqrt{x}+1}{\sqrt{x}+5}\\ =\dfrac{2(\sqrt{x}-5)+15-\sqrt{x}}{(\sqrt{x}-5)(\sqrt{x}+5)}.\dfrac{\sqrt{x}-5}{\sqrt{x}+1}\\ =\dfrac{(\sqrt{x}+5).(\sqrt{x}-5)}{(\sqrt{x}-5)(\sqrt{x}+5)(\sqrt{x}+1)}\\ =\dfrac{1}{\sqrt{x}+1}$
Xin 5 sao+ctlhn ạ.