`|x + 1/2| > 3`

  `=> -(x + 1/2) > 3` hoặc `x + 1/2 > 3`

`TH_1: -(x + 1/2) < 3`

`x + 1/2 < -3`

`x < (-3) - 1/2`

`x < (-6)/2 - 1/2`

`x < (-7)/2`

`TH_2: x + 1/2 > 3`

`x > 3 - 1/2`

`x > 6/2 - 1/2`

`x > 5/2`

         Vậy: `x < (-7)/2` hoặc `x > 5/2`

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