\(x^2\left(x^2-4\right)=3\left(x^2-4\right)\)
\(\Leftrightarrow x^2\left(x^2-4\right)-3\left(x^2-4\right)=0\)
\(\Leftrightarrow\left(x^2-3\right)\left(x^2-4\right)=0\)
\(\Leftrightarrow x^2-3=0\)hoặc \(x^2-4=0\)
\(\Leftrightarrow x^2=3\)hoặc \(x^2=4\)
\(\Leftrightarrow x=+-\sqrt{3}\)hoặc \(x=+-2\)