`4x^2-1=0`
`<=>(2x-1)(2x+1)=0`
`<=>[(2x-1=0),(2x+1=0):}`
`<=>[(2x=1),(2x=-1):}`
`<=>[(x=1/2),(x=-1/2):}`
Vậy `x=1/2` hoặc `x=-1/2`
Ta có: \(4x^2-1=0\)
\(\Leftrightarrow\left(2x-1\right)\left(2x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=-\dfrac{1}{2}\end{matrix}\right.\)