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Thread: Help with Algebra??

  1. #11
    Guest

    Re:Help with Algebra??

    You got me on that. My mind is shot.

  2. #12
    Guest

    Re:Help with Algebra??

    Okay, I'll see what I can do about some exsamples for you later (it's 1.45 am here now, and I'm on a Windows PC).

    Try this:

    2x/(x-2) + 4x/(x+1) contracted would be what?

  3. #13
    Guest

    Re:Help with Algebra??

    2x-4+4x+4

    Is that right?? Please reply back.

  4. #14
    Guest

    Re:Help with Algebra??

    2x / (x-2) + 4x / (x+1)

    first extend:
    (2x * (x + 1)) / ((x-2)*(x +1)) + (4x * (x-2)) / ((x-2)*(x+1))

    (2x^2 + 2x) / (x^2 - x - 1) + ( 4x^2 - 8x) / ( x^2 -x -1)

    contraction:

    (2x^2 +2x + 4x^2 -8x) / (x^2 - x - 1)

    and reduce the division a bit to make it pretty

    (6x^2 - 6x) / (x^2 - x -1)

  5. #15
    Guest

    Re:Help with Algebra??

    I'm really getting mad now. I don't understand nothing.

  6. #16
    Guest

    Re:Help with Algebra??

    Tell you what, tomorrow I'll post a set of exsamples in a notation that's less calculator like.

    kinda like your first post.

    I'll have to latex it or otherwise make a little picture for your too look at, it's MUCH easier to understand once you get a notation you are familiar with.

    And I'll make sure to do ALL the steps in moronic detail so it can't be misunderstood.

    sound good? (I'm going to sleep now... so you'll have to accept or whine loud, really loud, because I sleep like a rock)

  7. #17
    Guest

    Re:Help with Algebra??

    ok i accept.

  8. #18
    Mentor
    Join Date
    Jun 2001
    Posts
    1,672

    Re:Help with Algebra??

    Did LC confuse the hell out of you? Try this:

    2 3(x-1)
    --- + -------- =1
    x 5x

    Multiply both sides by x:
    2 3(x-1)
    --- + -------- = 1 x
    1 5

    Simplify it:
    3(x-1)
    2 + -------- = x
    5

    Multiple both sides by 5:
    10 + 3(x-1) = 5x

    Let's break up the paranthesis:
    10 + 3x - 3 = 5x

    Subtract 3x from both sides:
    10 - 3 = 5x - 3x

    Let's do the math:
    7 = 2x

    Divide both sides by 2:
    3.5 = x

    Swap sides, and there you have it:
    x = 3.5


    Next:

    4 1 5
    ----- - ----- = ------
    x-2 x x-2

    Let's multiple both sides by x-2:
    x-2
    4 - ------- = 5
    x

    Let's multiple both sides by x:
    4x - (x-2) = 5x

    Let's break up the paranthesis:
    3x + 2 = 5x

    Subtract 3x from both sides:
    2 = 2x

    Divide both sides by 2:
    1 = x

    Swap sides and there you have it:
    x = 1

    But of course there are 5 million other ways to solve these problems ...

  9. #19
    Guest

    Re:Help with Algebra??

    While I agree that in that exsample multipling with x is the easiest way, the general way to do these is divisor contraction - it works everytime where as the clever way of doing less work may be hard to apply to all targets.

    Of course if you are good at it, seeing an easier solution is often quicker, however doing it textbook style without thinking is my preferred method since I'm to lazy to look for loopholes.

    The idea behind divisor contraction is of course to get only one division, and thus be able to calculate more easily on it. Kinda like the first exsample which is probably the easiest ones to do.

    Oh and decimal notation will bite you in the ass, rounding off a fraction to get a real number is pure evil - if you use fractions throughout the problem and deliver your solution in decimal notation you are sure not to get rounding errors. Plus operations on fractions is dead easy.

    (2 / 3) * 3 = 6 / 3 = 2

    (2 / 3) / (3 / 2) = (2 * 3) / (3*2) = 6 / 6 = 1

    The idea behind using fractions is that rounding errors are amplified each time to round up, and in most computations a round error will result in an undesired result.

  10. #20
    Guest

    Re:Help with Algebra??

    I'm stuck on the same problem. I'm trying to do it on my own so i know how. Tell me is this right.

    I multiply both sides by 5x. I got 10x+3x-3=5x

    The problem is as follow.

    2 3(x-1)
    --- + -------- =1
    x 5x


    "Please reply back. Thanks."

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