Đáp án:
Giải thích các bước giải:
`(x-\sqrt{2})+3(x^2-2)=0`
`⇔(x-\sqrt{2})+3(x-\sqrt{2})(x+\sqrt{2})=0`
`⇔(x-\sqrt{2})+(x-\sqrt{2})(3x+3\sqrt{2})=0`
`⇔(x-\sqrt{2})(3x+3\sqrt{2}+1)=0`
`⇔`\(\left[ \begin{array}{l}x-\sqrt{2}=0\\x+\sqrt{2}+1=0\end{array} \right.\)
\(⇔\left[ \begin{array}{l}x=\sqrt{2}\\3x=-1-3\sqrt{2}\end{array} \right.\)
\(⇔\left[ \begin{array}{l}x=\sqrt{2}\\x=\dfrac{-1-3\sqrt{2}}{3}\end{array} \right.\)
\(⇔\left[ \begin{array}{l}x=\sqrt{2}\\x=\dfrac{-1}{3}+\sqrt{2}\end{array} \right.\)
Chọn `-\sqrt{2}` và `-\frac{1}{3}+\sqrt{2}`
