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Math Help - Answers Check & Question

  1. #1
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    Answers Check & Question

    Are these correct?

    1. Multiply:
    (10z+5)(z2 - 2z+10)

    10z3 - 15z2 + 90z + 50


    2. Divide:
    16r3 - 12r2+ 60r + 16
    ------------------------
    8r+2
    2(r2 - r +4)

    3. Divide Synthetically:
    (2m3 + 5m2 + 6m -4) / (m +1)

    2m2 + 3m + 3 R= -7/m+1

    4. Subtract 13r2 - 9r + 3 from 7r2- 4r - 8

    -6r2+ 13r +5


    5. Divide:
    18r3 - 9r2+34r +45
    --------------------
    6r + 5

    3r2 - 4r + 9

    6. Factor:
    uv2 - 4 - v2+ 4

    (u+1)(v2 + 4)


    7. Factor:
    x2(y-7)2 + 5x(y-7)2 +4(y-7)2

    (y-7)2(x+4)(x-1)

    8.Factor:
    x3 + 125

    (x+5)(x2-5x+25)

    9. Factor:
    16a4 - 1
    (4a2+1)(4a2- 1)

    10. If g(t) = 2t2+11t-10, find t such that g(t) = 11

    g(t) = 353


    11. Evaluate:
    4x2y2+2x2y - 3xy2- 3xy + 6 when x= -2 and y = 2

    -2

    12. If P(y) = 1/2y -1 then find y such that P(y)= -5

    P(y) = - 13/2


    And I need help setting up this problem:
    Solve this equation:
    n3+80n=18n2

    Would you set it up as n3+80n+18n2= 0 ?
    I'm not sure what my steps need to be to set it up to try and solve it.

    Thank you for any help!
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  2. #2
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    Re: Answers Check & Question

    allow me to introduce you to Wolfram Alpha ...

    expand (10z+5)*(z^2 - 2z+10) - Wolfram|Alpha
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  3. #3
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    Re: Answers Check & Question

    I've looked at Wolfram Alpha and many of what I input is not being understood. I am not sure what I am doing wrong with imputing the information? I really need to know if my answers are correct because these are being used as notes for my final tomorrow.
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  4. #4
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    Re: Answers Check & Question

    Quote Originally Posted by Kibbygirl View Post
    I've looked at Wolfram Alpha and many of what I input is not being understood. I am not sure what I am doing wrong with imputing the information? I really need to know if my answers are correct because these are being used as notes for my final tomorrow.
    Can you show what you tried at Wolfram Alpha that would not work.
    You might Look at this page..
    Using those examples may give you some ideas.
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  5. #5
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    Re: Answers Check & Question

    the following are incorrect ...

    4, 6, 7, 10, 11, and 12

    9 is incomplete

    n^3+80n=18n^2

    n^3-18n^2+80n = 0

    start by factoring out an n , then factor the resulting quadratic factor
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  6. #6
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    Re: Answers Check & Question

    #10 and #12 are ones that it doesn't seem to understand and I am unsure how to put them in so it can understand them. I didn't see it on the examples page.
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  7. #7
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    Re: Answers Check & Question

    Ok thank you. So 1-3, 5, 8 are all incorrect?
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  8. #8
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    Re: Answers Check & Question

    10. If g(t) = 2t^2+11t-10, find t such that g(t) = 11
    2t^2+11t-10 = 11

    2t^2+11t-21 = 0

    factor and solve

    12. If P(y) = 1/2y -1 then find y such that P(y)= -5
    \frac{1}{2y} - 1 = -5

    \frac{1}{2y} = -4

    -\frac{1}{4} = 2y

    -\frac{1}{8} = y
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  9. #9
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    Re: Answers Check & Question

    Nevermind, I misread your above post.
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  10. #10
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    Re: Answers Check & Question

    Quote Originally Posted by Kibbygirl View Post
    #10 and #12 are ones that it doesn't seem to understand and I am unsure how to put them in so it can understand them. I didn't see it on the examples page.
    Well look at this,
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  11. #11
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    Re: Answers Check & Question

    How would I put #7 above into the Wolfram site? This problem:
    Factor:
    x2(y-7)2 + 5x(y-7)2 +4(y-7)2
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  12. #12
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    Re: Answers Check & Question

    Quote Originally Posted by Kibbygirl View Post
    How would I put #7 above into the Wolfram site? This problem:
    Factor:
    x2(y-7)2 + 5x(y-7)2 +4(y-7)2
    link ...

    factor x^2(y-7)^2 + 5x(y-7)^2 +4(y-7)^2 - Wolfram|Alpha
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  13. #13
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    Re: Answers Check & Question

    Thanks skeeter. I typed it in but I must have had spaces in the wrong spot. For #6 above - which I see I had a typo and left off the u on the end after the second 4... --- ; uv2 - 4 - v2+ 4u is the correct answer (u-1)(v2+4)?
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