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anonymous

  • one year ago

I got this question wrong on my College Algebra test and i don't know why it is wrong. please help.

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  1. anonymous
    • one year ago
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    Write in interval notation... \[-7 \le x < 9\] and i put \[[-7, \infty) (-\infty, 9)\] How is this wrong?

  2. anonymous
    • one year ago
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    @hartnn can you help explain this please

  3. kropot72
    • one year ago
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    Put into words, the expression says: x is equal to or greater than negative 7, and x is less than 9.

  4. jackthegreatest
    • one year ago
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    first of all, x does not go on to infinite

  5. jackthegreatest
    • one year ago
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    i just had this lesson in math

  6. hartnn
    • one year ago
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    which also means x is between -7 and 9 (-7 included) what you answered meant: x is greater than -7 till infinity, and x is less than 9 till -infinity

  7. kropot72
    • one year ago
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    You can find how to express this here: http://www.mathwords.com/i/interval_notation.htm

  8. jackthegreatest
    • one year ago
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    the answer should be [-7,9) i am almost certain

  9. hartnn
    • one year ago
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    |dw:1442686985618:dw|

  10. jackthegreatest
    • one year ago
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    @hartnn is right

  11. kropot72
    • one year ago
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    [-7, 9)

  12. hartnn
    • one year ago
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    |dw:1442687043917:dw|

  13. anonymous
    • one year ago
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    I don't need graphs.

  14. hartnn
    • one year ago
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    ok, what doubt you still have? :)

  15. anonymous
    • one year ago
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    interval notation is like a basket, lets say of a row of kittens: kitten a, b, c, d, e. [b, d] means basket contains b and d: {b, c, d} (a, e) means the basket does not include a and e: a {b, c, d} e what you wrote was two baskets. one that contains {-7 and everything above in the world} and one that contains {everything below in the world up to but not including 9} 9 is out here. You need an additional relationship between the two to say what if you mean "AND" or "OR".. (another way of saying it is, only the overlap of the two baskets, known as INTERSECTION of the two... or anything in both baskets, you dont care, known as the UNION of the two.) Since you didn't indicate a relation, you pretty much said two baskets that contain everything in the world. :) the correct basket is [-7, 9).. only the stuff in between -7 and 9, INCLUDING -7 but NOT including 9. Technically the same meaning but you haven't learned it yet, is the INTERSECTION of the two baskets you wrote: The basket containing only the overlap or what's in both baskets. Which simplifies to [-7, 9)

  16. anonymous
    • one year ago
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    sorry UNION is anything in in EITHER basket is more correct wording. :)

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