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a123

  • 4 years ago

Can somebody help me? I've tried to solve this problem and I just can't manage to get the right answer: |7x + 2| > -2

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  1. satellite73
    • 4 years ago
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    true for all x by inspection absolute value is positive, so it is always bigger than -2

  2. a123
    • 4 years ago
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    how do you write it like a < x < b or something like that?

  3. a123
    • 4 years ago
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    i keep getting x > 0

  4. a123
    • 4 years ago
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    and x < 4/7

  5. satellite73
    • 4 years ago
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    it is all real numbers x can be anything. do not try to solve this using algebra. absolute value of anything is always greater than or equal to 0, so it must be always greater than -2. it doesn't matter what you put in for x, positive number or negative number

  6. a123
    • 4 years ago
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    oh

  7. satellite73
    • 4 years ago
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    \[(-\infty,\infty)\]

  8. a123
    • 4 years ago
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    wait, why is one of the infinity symbols negative if x is always greater than or equal to 0?

  9. LagrangeSon678
    • 4 years ago
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    what satellite means by (-inf,inf) is that you can plug any x value into the inequality, you can plug in -20000, 200, 3,4, -5, it dosent matter, you will still get a value greater than or equal to zero

  10. a123
    • 4 years ago
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    i still don't understand why, if you plug in a negative number, it comes out to be greater than or equal to zero

  11. LagrangeSon678
    • 4 years ago
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    beacuse of the absolute value, you see the absolute value guarantees you that the value you get out will be positive or zero, it cannot be negative

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spraguer (Moderator)
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