\(4x^4-11x^2+6=0\)
\(\Leftrightarrow4x^4-8x^2-3x^2+6=0\)
\(\Leftrightarrow4x^2\left(x^2-2\right)-3\left(x^2-2\right)=0\)
\(\Leftrightarrow\left(x^2-2\right)\left(4x^2-3\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x^2-2=0\\4x^2-3=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\pm\sqrt{2}\\x=\pm\sqrt{\frac{3}{4}}\end{cases}}\)
\(S=\left\{\pm\sqrt{2};\pm\sqrt{\frac{3}{4}}\right\}\)
nếu có sai bn thông cảm nha