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Math Help - I need help evaluating this numbers

  1. #1
    Junior Member Cyberman86's Avatar
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    Question I need help evaluating this numbers

    x=3/10

    evaluate
    y=5x^2-3x+4
    y=5(3/10)^2 -3(3/10)-1 (How do you evaluate this part, step by step)

    y=71/20
    (This is the answer)
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  2. #2
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    Quote Originally Posted by Cyberman86 View Post
    x=3/10

    evaluate
    y=5x^2-3x+4
    y=5(3/10)^2 -3(3/10)-1 (How do you evaluate this part, step by step)

    y=71/20 (This is the answer)
    Cyberman, please consider the following.

    y=5\left(\frac{3}{10}\right)^2 -3\left(\frac{3}{10}\right)+4

    y=5\left(\frac{3^2}{10^2}\right) -3\left(\frac{3}{10}\right)+4

    y=5\left(\frac{9}{100}\right) -3\left(\frac{3}{10}\right)+4

    y=\frac{5\times 9}{100} -\frac{3\times 3}{10}+4

    y=\frac{45}{100} -\frac{9}{10}+4

    To finish the problem you must create a common denominator

    y=\frac{45}{100} -\frac{90}{100}-\frac{400}{100}

    y=\frac{45-90-400}{100}

    Now finish and simplfy.
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  3. #3
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    Quote Originally Posted by pickslides View Post
    y=\frac{45-90-400}{100}
    Last term should be + 400/100
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  4. #4
    Master Of Puppets
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    Quote Originally Posted by Wilmer View Post
    Last term should be + 400/100
    Thanks Wilmer

    I did notice that it could be the case but after reviewing this

    Quote Originally Posted by Cyberman86 View Post
    x=3/10

    evaluate
    y=5x^2-3x+4
    y=5(3/10)^2 -3(3/10)-1 (How do you evaluate this part, step by step)

    y=71/20 (This is the answer)

    I was not sure which sign it could be? How can a +4 become a -1?
    Posters should be more careful if they are serious about their education.
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  5. #5
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    Quote Originally Posted by pickslides View Post
    y=\frac{45}{100} -\frac{9}{10}+4
    To finish the problem you must create a common denominator
    y=\frac{45}{100} -\frac{90}{100}-\frac{400}{100}
    I only looked at these 2 lines...hence noticed the switch from + to -
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  6. #6
    Master Of Puppets
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    I think the poster should re-supply the question.
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  7. #7
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by pickslides View Post
    Thanks Wilmer

    I did notice that it could be the case but after reviewing this




    I was not sure which sign it could be? How can a +4 become a -1?
    Posters should be more careful if they are serious about their education.
    I would say + because 45-90 < 0 and so for the answer to be > 0 it would need to be +400
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