ĐKXĐ: ...
\(\sqrt{x-3}=1-y\) (\(y\le1\))
\(\Rightarrow x-3=\left(1-y\right)^2=y^2-2y+1\)
\(\Rightarrow x=y^2-2y+4\)
Thế xuống dưới:
\(\sqrt{y^2-2y+4-2y}+2\sqrt{y^2-2y+4+8y+5}=8\)
\(\Leftrightarrow\sqrt{\left(2-y\right)^2}+2\sqrt{\left(y+3\right)^2}=8\)
\(\Leftrightarrow2-y+2\left|y+3\right|=8\)
\(\Rightarrow2\left|y+3\right|=y+6\Rightarrow\left[{}\begin{matrix}y=0\\y=-4\end{matrix}\right.\) (đều thỏa mãn)
\(\Rightarrow x=y^2-2y+4=...\)