Solving inequalities?

Solve:

| 0.5x – 1 | =< | x + 2 |

x = -6 and x = -2/3

For this to be true, x is of any value between x = -6 and x = -2/3. I’ve also included my range to x values greater than x = -2/3.
In essence, any value from -6 and greater makes the inequality true.
However, I was marked wrong. What am I missing?

✅ Answers

? Best Answer

  • | 0.5x – 1 | ≤ | x + 2 |
    =>
    0.5x – 1 ≤ | x + 2 |
    and
    -| x + 2 | ≤ 0.5x – 1
    =>
    0.5x – 1 ≤ x + 2 or x + 2 ≤ 1 – 0.5x
    and
    1 – 0.5x ≤ x + 2 or x + 2 ≤ 0.5x – 1
    =>
    -6 ≤ x or x ≤ -2/3 (satisfied by every x)
    and
    -2/3 ≤ x or x ≤ -6
    =>
    x ∈ (-∞,-6]∪[-2/3,∞)

    See plot:
    http://www.wolframalpha.com/input/?i=plo…

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