2 câu trả lời
Lời giải:
`|2x - 1| = 3`
TH1:
`2x - 1 = 3`
`2x = 3 + 1`
`2x = 4`
`x = 4 : 2`
`x = 2`
TH2:
`2x - 1 = -3`
`2x = -3 + 1`
`2x = -2`
`x = -2 : 2`
`x = -1`
Vậy `x = 2` hoặc `x = -1`
`| 2x - 1 |` `=` `3`
`=>` `| 2x - 1 |` `=` `| 3 |` `=` `| -3 |`
`=>` $\left[\begin{matrix} 2x-1=3\\ 2x-1=-3\end{matrix}\right.$
`=>` $\left[\begin{matrix} 2x=4\\ 2x=-2\end{matrix}\right.$
`=>` $\left[\begin{matrix} x=2\\ x=-1\end{matrix}\right.$
Vậy `x` $\in$ `{ 2 ; -1 }`