Bài 1:
$4x+2y+2z-4\sqrt{xy}-4\sqrt{xz}+2\sqrt{yz}-10\sqrt{z}-6\sqrt{y}+34=0 \\\iff (4x+y+z-4\sqrt{xy}-4\sqrt{xz}+2\sqrt{yz})+(y-6\sqrt{y}+9)+(z-10\sqrt{z}+25)=0 \\\iff (2\sqrt{x}-\sqrt{y}-\sqrt{z})^2+(\sqrt{y}-3)^2+(\sqrt{z}-5)^2=0 \\\iff \left\{\begin{matrix} 2\sqrt{x}-\sqrt{y}-\sqrt{z}=0 \\ \sqrt{y}-3=0 \\ \sqrt{z}-5=0 \end{matrix}\right. \\\iff \left\{\begin{matrix} x=16 \\ y=9 \\ z=25 \end{matrix}\right.$