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Math Help - Can someone help me fast?

  1. #1
    Newbie
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    Exclamation Can someone help me fast?

    I need help answering these problems. If anyone can help me it would be greatly appreciated! Thank you!

    Solve the Equation
    1.x^2/3+5X^1/3+4+0
    A.plus or minus 3i and plus or minus square root of 3
    B. 3, square root of 3
    C. plus or minus 3, plus or minus i square root of 3
    d.plus or minus 3

    2.If f(x)+2x^2+x and g(x)+2x-l, what is [f o g](x)?
    A.2x^2-7x+6
    B. 2x^2-7x+8
    C. 2x^2-3x+2
    D. x^2-3x+6
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  2. #2
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    Anybody?
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  3. #3
    MHF Contributor
    Joined
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    Some of reasons why nobody wants to solve your problems here:
    1. The two poblems are not clear. The are no spaces to separate the terms.
    2. You used "+" for the equal sign "=".
    3. You showed 4 possible answers per problem, like multiple choice, but none of them are correct. Either those are your own solutions, or you copied the wrong solutions for the two problems.

    If i understood your intention, then,

    1.x^2/3+5X^1/3+4+0

    I assume you mean
    x^(2/3) +5x^(1/3) +4 = 0

    Let y = x^1/3, so,
    y^2 +5y +4 = 0
    (y+4)(y+1) = 0

    y+4 = 0
    y = -4
    Changing back to y = x^(1/3),
    x^(1/3) = -4
    Raise both sides to their 3rd power, or cube them,
    x = (-4)^3 = -64

    y+1 = 0
    y = -1
    x^(1/3) = -1
    x = (-1)^3 = -1

    Therefore, x = -64 or -1. ........answer.

    ------------------------
    2.If f(x)+2x^2+x and g(x)+2x-l, what is [f o g](x)?

    I assume you mean
    iF f(x) = 2x^2 +x, and g(x) = 2x -1, what is [f o g](x)?

    [f o g](x) = 2(2x -1)^2 +(2x -1)
    = 2(4x^2 -4x +1) +2x -1
    = 8x^2 -8x +2 +2x -1
    = 8x^2 -6x +1 ........answer.
    Last edited by ticbol; April 27th 2005 at 12:48 PM.
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