~ Bạn tham khảo ~
`a, 2 |3x-1 |+1=5`
`2 |3x-1 |=5-1`
`2 |3x-1 |=4`
` |3x-1 | = 4:2`
` |3x-1 |=2`
\(\left[ \begin{array}{l}3x-1=2\\3x-1=-2\end{array} \right.\)
\(\left[ \begin{array}{l}3x=3\\3x=-1\end{array} \right.\)
\(\left[ \begin{array}{l}x=1\\x=-1/3\end{array} \right.\)
Vậy `x ∈ { 1 ; -1/3 }`
`b, |x/2 - 1 | = 3`
`=> x/2 - 1 = 3`
` x/2 = 4`
`x/2 = 8/2`
`=> x = 8`
`=> x/2 - 1= -3`
`x/2 = -2`
`x/2 = -4/2`
`=> x = -4`
Vậy ` x ∈ { 8 ; -4 }`
