ĐK:...
$(1)\Leftrightarrow (1-y)(\sqrt{x-y}-1)+(x-y-1)=(x-y-1)\sqrt{y}$
$\Leftrightarrow (x-y-1)(\frac{1-y}{\sqrt{x-y}+1}+1-\sqrt{y})=0$
$\Leftrightarrow (x-y-1)(1-y)(\frac{1}{\sqrt{x-y}+1}+\frac{1}{\sqrt{y}+1})=0$
$\Leftrightarrow x=y+1 or y=1$(do(...)>0)
*)$y=1$:
(2)tt:$9-3x=0\Leftrightarrow x=3$
*)$x=y+1$
(2)tt:$2y^{2}+3y-2=\sqrt{1-y}$
$\Leftrightarrow 2(y^{2}+y-1)=\sqrt{1-y}-y$
$\Leftrightarrow(y^{2}+y-1)(\frac{1}{\sqrt{1-y}+y}+2)=0$
$\Leftrightarrow y^{2}+y-1=0 \Leftrightarrow y=\frac{-1+\sqrt{5}}{2}$(t/m đk)$\Rightarrow x=\frac{1+\sqrt{5}}{2}$
KL:....