Question

Tìm x

a) \(5x\left(x-2000\right)-x+2000=0\)

b) \(x^3-13x=0\)

Answer 1

a,\(5x\left(x-2000\right)-x+2000=0\)

\(\Rightarrow5x\left(x-2000\right)-\left(x-2000\right)=0\)

\(\Rightarrow\left(x-2000\right)\left(5x-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x-2000=0\\5x-1=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=2000\\x=\dfrac{1}{5}\end{matrix}\right.\)

b,\(x^3-13x=0\)

\(\Rightarrow x.x^2-13x=0\)

\(\Rightarrow x\left(x^2-13\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x^2-13=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x^2=13\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x=\sqrt{13}\end{matrix}\right.\)