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greeneyes<3

  • 2 years ago

Find the domain of the expression: 1. 6x^2-9, x>0 2. (x^2-x-12)/(x^2-8+16) Please show steps or explain them to me! Thank you!

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  1. munaali
    • 2 years ago
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    -9

  2. greeneyes<3
    • 2 years ago
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    is it like all real numbers, or can you please explain?

  3. munaali
    • 2 years ago
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    yes

  4. greeneyes<3
    • 2 years ago
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    it still does not make sense, x has to be > 0

  5. munaali
    • 2 years ago
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    the real numer has negive

  6. greeneyes<3
    • 2 years ago
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    @jim_thompson5910 can you help me with these two problems?

  7. jim_thompson5910
    • 2 years ago
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    by default, all polynomials have a domain of the set of all real numbers

  8. jim_thompson5910
    • 2 years ago
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    but because it clearly states that x > 0, that means the domain is x > 0, so the domain is the set of positive real numbers

  9. jim_thompson5910
    • 2 years ago
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    to find the domain of (x^2-x-12)/(x^2-8x+16), set the denominator equal to zero and solve for x those two solutions will be values you exclude from the domain

  10. greeneyes<3
    • 2 years ago
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    Thank you! Now my answers are: 1. x=all + real numbers 2. x cannot=+ or - 4, and -2 is that right?

  11. jim_thompson5910
    • 2 years ago
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    the first one is correct, but the second is not

  12. jim_thompson5910
    • 2 years ago
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    hint: x^2 - 8x + 16 factors to (x-4)(x-4)

  13. greeneyes<3
    • 2 years ago
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    so x cannot equal 4, or -2 ?

  14. jim_thompson5910
    • 2 years ago
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    how are you getting -2?

  15. greeneyes<3
    • 2 years ago
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    oh nevermind I see what I was doing wrong, was separating x^2 and -8x and solving them each for -16 separately. So the answer is just x cannot = 4 ?

  16. jim_thompson5910
    • 2 years ago
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    bingo, the domain is the set of all real numbers but x cannot equal 4

  17. greeneyes<3
    • 2 years ago
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    Okay thank you! :)

  18. jim_thompson5910
    • 2 years ago
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    you're welcome

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