Question

tìm x ,b iết :

x⁴ +4 =5x²

Answer 1

\(x^4+4=5x^2\Rightarrow x^4-5x^2+4=0\Rightarrow\left(x-2\right)\left(x-1\right)\left(x+1\right)\left(x+2\right)=0\Rightarrow\left[{}\begin{matrix}x=2\\x=1\\x=-1\\x=-2\end{matrix}\right.\)

Answer 2

Ta có: \(x^4+4=5x^2\)

\(\Leftrightarrow x^4-5x^2+4=0\)

\(\Leftrightarrow\left(x-1\right)\left(x+1\right)\left(x-2\right)\left(x+2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-1\\x=2\\x=-2\end{matrix}\right.\)