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If I have four unknown variables, x, y, j, and k, but know the values of x*j, y/k, and k/j, and x*j == y/k

How do I go about getting the values of the individual unknown variables?

Comments
  • 7
    You'll need one more equation for the four values. Right now you have three
  • 0
    @iiii hey thanks iii. will any equation do?
  • 5
    Fuck I thought I was done with middle school algebra systems of equations
  • 3
    Systems of equations!
    I loved them 😄
  • 0
    @Root how much for you to do my homework. The current math teacher isn't hardcore enough. I need a professional to torture me with numbers.
  • 6
    let a = x*j = y/k
    let b = k/j

    ab = xk = y/j

    since a and b are known, if you find x, you will get k = ab/x and j = a/x, y = ak = a²b/x

    That's all the variables

    If you know y, j = y/ab, x = a/j = a²b/y, k = y/a

    In short, you need one more variable, this is not enough, but this can help you find patterns.
  • 2
    @theabbie thank you abbie. Figured it was going to be something like that.

    Also voice-to-text insisted your handle is "applepie" and not "abbie."
  • 2
    @Wisecrack not any, but one that gives additional information, so that two if them cannot be reduced to just one.
  • 3
    Not just any extra equation will work if you want unique values of x, y, j, k.

    Any (x, y) on the hyperbola xy = a²b (where a = x*j = y/k and b = k/j) will satisfy your current constraints.
    For each of these (x, y), you get a (j, k).

    If you want a unique set of values, the extra equation when converted in terms of x, y must intersect with the above hyperbola at only one point otherwise you would get 2 or more solutions.
  • 2
    Helpful answer, and I'm starting to grasp what you're explaining.

    Suppose we have another unknown variable d.

    We know d*y and we know d*k, but we don't obviously know d, y or k.

    Additionally you know the
    value of x/d

    But obviously not x or d alone.
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