Question

Với x = ......... thì x^2( x^2 - 4 ) = 3( x^2 - 4).

Giair giúp mình với mọi người.

Answer 1

\(x^2\left(x^2-4\right)=3\left(x^2-4\right)\)

\(\Rightarrow x^2\left(x^2-4\right)-3\left(x^2-4\right)=0\)

\(\Rightarrow\left(x^2-4\right)\left(x^2-3\right)=0\)

\(\Rightarrow\left[\begin{array}{nghiempt}x^2-4=0\\x^2-3=0\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}\left[\begin{array}{nghiempt}x=2\\x=-2\end{array}\right.\\\left[\begin{array}{nghiempt}x=\sqrt{3}\\x=-\sqrt{3}\end{array}\right.\end{array}\right.\)

Vậy x=2; x= - 2 ; x=\(\sqrt{3}\) ; x=\(-\sqrt{3}\)

Answer 2

Có : \(x^2\left(x^2-4\right)=3\left(x^2-4\right)\)

\(\Leftrightarrow x^2\left(x^2-4\right)-3\left(x^2-4\right)=0\)

\(\Leftrightarrow\left(x^2-4\right)\left(x^2-3\right)=0\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x^2-4=0\\x^2-3=0\end{array}\right.\) \(\Leftrightarrow\left[\begin{array}{nghiempt}x^2=4\\x^2=3\end{array}\right.\) \(\Leftrightarrow\left[\begin{array}{nghiempt}x=2;x=-2\\x=\sqrt{3};x=-\sqrt{3}\end{array}\right.\)

Vậy \(x=-2;x=2;x=-\sqrt{3};x=\sqrt{3}\)