$\sqrt{4x-20}-3\sqrt{5+x}+_{}$ $\frac{4}{3}\sqrt{9x+45}=6$ $ĐK:_{}$ $x_{}$ $\geq-5$
$⇔\sqrt{4.(x+5)}-3\sqrt{x+5}_{}$ $+\frac{4}{3}.\sqrt{9.(x+5)}=6$
$⇔\sqrt{4}.\sqrt{x+5}-3\sqrt{x+5}_{}$ $+\frac{4}{3}.\sqrt{9}.\sqrt{x+5}=6$
$⇔2.\sqrt{x+5}-3\sqrt{x+5}_{}$ $+\frac{4}{3}.3\sqrt{x+5}=6$
$⇔2\sqrt{x+5}-3\sqrt{x+5}+4\sqrt{x+5}=6_{}$
$⇔3\sqrt{x+5}=6_{}$
$⇔\sqrt{x+5}=2_{}$
$⇔x+5=4_{}$
$⇔x=-1_{}$ $(TMĐK)_{}$
$Vậy_{}$ $x_{}=-1$
