For Algebra Fans

DonM46
DonM46 Posts: 771 Member
edited September 26 in Chit-Chat
You lost ONE pound last week?
Or was it TWO?
No matter; they are the same.
Here's proof:

I can assume that x = y.
As long as I perform the same mathematical operation on both sides of the equals sign, I've not changed the equality.
So, multiply both sides by y to get
xy = y^2
(where y^2 is read as y squared)
Now, subtract x^2 from both sides to get
xy - x^2 = y^2 - x^2
There is a common x term on the left side, so I can factor it out to get
x (y - x)
The right side of the equation can be factored into the product (y - x) (y + x)
Making these substitutions, the equality becomes
x (y - x) = (y - x) (y + x)
Note that there is a common term (y - x) on both sides, so I can divide it out (or cancel it) to get
x = (y + x)
The original assumption was that x and y were equal, so I'll substitute x for the y term
x = x + x
or, simplifying
x = 2x
Since there is an x on each side, I'll divide both sides by x, and recognizing that x / x = 1, this leads to
1 = 2.

Replies

  • allison7922
    allison7922 Posts: 276 Member
    yeah...I failed Algebra....
  • robin52077
    robin52077 Posts: 4,383 Member
    hmmm...that's cool..i did it out and you didn't screw anything up.

    x and y are both zero
    :bigsmile: then it works

    but then that means you lost NO weight! bwahahahaha!
  • Creiche
    Creiche Posts: 264 Member
    Ah, I remember this one...always a good one. Had to stare at it a while the first time before I got it. I won't ruin it for it everyone. :)
  • Creiche
    Creiche Posts: 264 Member
    x and y are both zero
    :bigsmile: then it works

    Doesn't quite work if x and y are both zero...hint hint. :)
  • Ninjitsu
    Ninjitsu Posts: 163
    There are issues with the algebraic expression; however, it was entertaining to try to solve for the heck of it.

    :p
  • pyro13g
    pyro13g Posts: 1,127 Member
    Fail!
  • Laceylala
    Laceylala Posts: 3,094 Member
    The title alone made my head hurt...then I read it...and I am pretty sure I burned the same calories reading it as I do running for two minutes on the treadmill!!

    Thanks for posting!
  • thebigwindmill
    thebigwindmill Posts: 98 Member
    x = 2x
    Since there is an x on each side, I'll divide both sides by x, and recognizing that x / x = 1, this leads to
    1 = 2.


    Common mistake. If x = 0 then you just divided by zero and only Chuck Norris can do that. :tongue:

    (not sure if this works for the (y - x) term too further up the equation. That one seems plausible.)


    Anyway, you would actually wanna subtract x from both sides which gets you 0 = x

    Thanks for the math exercise! I miss math!
  • zave
    zave Posts: 238
    The title alone made my head hurt...then I read it...and I am pretty sure I burned the same calories reading it as I do running for two minutes on the treadmill!!

    Thanks for posting!

    Bwahahahaha!!! Yup, soon as I saw Algebra and fan together. I ran away. Which had to burn something.
  • thumper44
    thumper44 Posts: 1,464 Member

    .
    .
    .
    .
    x (y - x) = (y - x) (y + x)
    Note that there is a common term (y - x) on both sides, so I can divide it out (or cancel it) to get
    x = (y + x)
    The original assumption was that x and y were equal, so I'll substitute x for the y term
    x = x + x
    or, simplifying
    x = 2x
    Since there is an x on each side, I'll divide both sides by x, and recognizing that x / x = 1, this leads to
    1 = 2.
    I believe the flaw is you cannot divide by ( y - x ). Since y - x = 0.
  • TDGee
    TDGee Posts: 2,209 Member
    Not meaning to be a jerk, but do you get outside much? :bigsmile:
    I almost went to High School on the five year plan...

    Ted
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