\(x^2+y^2+z^2=4x-2y+6z-14\)
\(\Leftrightarrow x^2-4x+4+y^2+2y+1+z^2-6z+9=0\)
\(\Leftrightarrow\left(x-2\right)^2+\left(y+1\right)^2+\left(z-3\right)^2=0\)
\(\Rightarrow\hept{\begin{cases}x-2=0\\y+1=0\\z-3=0\end{cases}\Rightarrow\hept{\begin{cases}x=2\\y=-1\\z=3\end{cases}}}\)
\(\Leftrightarrow\) \(x^2\)+ \(y^2\) + \(z^2\) - \(4x\)+ \(2y\) - \(6z\) + \(14\) \(=\) \(0\)
\(\Leftrightarrow\) ( \(x^2\) - \(4x\) + \(4\) ) + ( \(y^2\) + \(2y\) + \(1\) ) \(=\) \(0\)
\(\Leftrightarrow\) ( \(x-2\))2 + \(\left(y+1\right)^2\) + \(\left(z-3\right)^2\) \(=\) \(0\)
\(\Leftrightarrow\) \(\hept{\begin{cases}x=2\\y=-1\\z=3\end{cases}}\)
ờ đúng ko vậy thanh nguyên chỉ có nhân =0 mới được phép tách ra chứ
