Question

Tìm x biết:

a)      \({x^2} - 4x = 0\)

b)      \(2{x^3} - 2x = 0\) 

Answer 1

a, \(x^2-4x=0\\ \Leftrightarrow x\left(x-4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=4\end{matrix}\right.\)

b, \(2x^3-2x=0\\ \Leftrightarrow2x\left(x^2-1\right)=0\\ \Leftrightarrow2x\left(x-1\right)\left(x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\\x=-1\end{matrix}\right.\)