Tìm x , y , z bt : x mũ 2 + 2x + y mũ 2 – 6y + 4z mũ 2 – 4z + 11 = 0

2 bình luận về “Tìm x , y , z bt : x mũ 2 + 2x + y mũ 2 – 6y + 4z mũ 2 – 4z + 11 = 0”

1. x^2 + 2x + y^2 – 6y + 4x^2 – 4z +11=0

   => (x^2 +2x + 1) + (y^2 -6y + 9)+(4z^2 -4x +1)=0

   => (x+1)^2 + (y-3)^2 + (2z-1)^2 =0

   ⇒ $\{\begin{array}{l}(x+1{)}^2=0\\ (y-3{)}^2=0\\ (2z-1{)}^2=0\end{array}$

   => $\{\begin{array}{l}x+1=0\\ y-3=0\\ 2z-1=0\end{array}$

   => $\{\begin{array}{l}x=-1\\ y=3\\ z={\displaystyle \frac{1}{2}}\end{array}$

   Vậy x=-1; y=3; z=1/2

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