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Math Help - Algebraic fractions

  1. #1
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    Algebraic fractions

    Questions I couldn't answer:

    x^2 - 25/25 + 5x

    I can factorize the numerator but not the denominator
    I'm familiar with factorizing, canceling and expanding but I've never confronted something like 5x + 25 to expand/factorize.
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  2. #2
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    Re: Algebraic fractions

    (2.5 x 10^9)/(5 x 10^3)

    in standard form. this isn't algebra but I'm hoping anybody has the patience to answer both.

    Write as a single fraction in it's simplest form:

    2x/x-1 - 7x-3/x^2-1

    Please explain how you got these answers too, in the most efficient method.

    Thanks!
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  3. #3
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    Re: Algebraic fractions

    Quote Originally Posted by Ashir View Post
    Questions I couldn't answer:

    x^2 - 25/25 + 5x

    I can factorize the numerator but not the denominator
    I'm familiar with factorizing, canceling and expanding but I've never confronted something like 5x + 25 to expand/factorize.
    5x+25, these two terms have a common factor 5 thus 5x+25 = 5(x+5)
    Thanks from Ashir
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  4. #4
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    Re: Algebraic fractions

    Quote Originally Posted by Ashir View Post
    (2.5 x 10^9)/(5 x 10^3)
    2.5 * 10^9 / (5 * 10^3)
    = 2.5 * 10^9 * 10^-3 / 5
    = 5/2 * 10^6 / 5
    = 5 * 10^6 / 10
    = 5 * 10^5

    Hope we're not doing your homework!!
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  5. #5
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    Re: Algebraic fractions

    Quote Originally Posted by Ashir View Post
    Questions I couldn't answer:

    x^2 - 25/25 + 5x

    I can factorize the numerator but not the denominator
    I'm familiar with factorizing, canceling and expanding but I've never confronted something like 5x + 25 to expand/factorize.
    Please use brackets where they're needed, or else learn some LaTeX. As written, your expression is \displaystyle \begin{align*} x^2 - \frac{25}{25} + 5x \end{align*}...
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  6. #6
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    Re: Algebraic fractions

    Quote Originally Posted by Ashir View Post
    ...

    Write as a single fraction in it's simplest form:

    2x/x-1 - 7x-3/x^2-1

    Please explain how you got these answers too...
    I am assuming you mean:

    \frac{2x}{x-1}-\frac{7x-3}{x^2-1}

    First, factor the denominators:

    \frac{2x}{x-1}-\frac{7x-3}{(x+1)(x-1)}

    Now it is clear what we need to multiply the numerator and denominator of the first term with to get a common denominator:

    \frac{2x}{x-1}\cdot\frac{x+1}{x+1}-\frac{7x-3}{(x+1)(x-1)}

    Can you finish?
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  7. #7
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    Re: Algebraic fractions

    Quote Originally Posted by MarkFL2 View Post
    Can you finish?
    No, I'm too busy. Could you finish it for me?
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  8. #8
    MHF Contributor MarkFL's Avatar
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    Re: Algebraic fractions

    Quote Originally Posted by Wilmer View Post
    No, I'm too busy. Could you finish it for me?
    Ding! Fries are done.
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  9. #9
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    Re: Algebraic fractions

    Quote Originally Posted by Siron View Post
    5x+25, these two terms have a common factor 5 thus 5x+25 = 5(x+5)
    How could I not have saw that? Thanks.

    Quote Originally Posted by Wilmer View Post
    2.5 * 10^9 / (5 * 10^3)
    = 2.5 * 10^9 * 10^-3 / 5
    = 5/2 * 10^6 / 5
    = 5 * 10^6 / 10
    = 5 * 10^5

    Hope we're not doing your homework!!
    Not following you. This area is very new to me, in fact we just started this week.

    Nope, you're correcting the questions I didn't get right in an exam :0)

    Quote Originally Posted by MarkFL2 View Post
    I am assuming you mean:

    \frac{2x}{x-1}-\frac{7x-3}{x^2-1}

    First, factor the denominators:

    \frac{2x}{x-1}-\frac{7x-3}{(x+1)(x-1)}

    Now it is clear what we need to multiply the numerator and denominator of the first term with to get a common denominator:

    \frac{2x}{x-1}\cdot\frac{x+1}{x+1}-\frac{7x-3}{(x+1)(x-1)}

    Can you finish?
    2X x X+1 = 2X+2 right? Or does the constant multiplied with the coefficient of the first term only apply to brackets?

    And otherwise I'm lost on what I do next. We're revisiting this area after a year or so.
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  10. #10
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    Re: Algebraic fractions

    Quote Originally Posted by Ashir View Post
    2X x X+1 = 2X+2 right?
    Please use * for multiplication sign; and small "x" for variable...; and brackets when necessary...

    2x * (x + 1) = 2x^2 + 2x ; everything inside brackets is multiplied by what's outside...
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  11. #11
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    Re: Algebraic fractions

    Forgot to times 2x by x sorry. Lost a good few marks on the exam because of clumsy mistakes
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  12. #12
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    Re: Algebraic fractions

    Quote Originally Posted by Ashir View Post
    Forgot to times....
    to MULTIPLY....
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  13. #13
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    Re: Algebraic fractions

    We say times here in England :P
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  14. #14
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    Re: Algebraic fractions

    Quote Originally Posted by cobooboc View Post
    I do not know why I proposed to be deleted, but I really do not understand that, can anyone give me an explanation?Or we do not have a common language.
    remove the commercial link from your signature line ... thank you.
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  15. #15
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    Re: Algebraic fractions

    Back on topic.
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