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Find 2x + y for the system:

  1. Jul 15, 2005 #1
    the system is:

    y=x^2 - x - 8

    the answer is: 1 and 28

    Can someone break this down how they arrived at these figures?

    thank you.
  2. jcsd
  3. Jul 15, 2005 #2
    Set them equal to each other to solve for x, then plug the corresponding y values in to find 2x + y.
  4. Jul 15, 2005 #3


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    Gold Member

    Or you can go to http://www.softintegration.com/chhtml/lang/lib/libch/plot/cgi_func.html

    go down the page and put into "Number of Data Sets to Plot : 2", because you have two equations.

    Then you click submit, and in next page you enter your functions:

    Curve #1
    y= pow(x,2) -x -8

    Curve #2

    Now as you can see your two graphs intersect each other at the point of your x and y solutions. There are 2 points that satisfy this system of equations.

    And as for answer (Find 2x+y) there are 2 answers to that question: 34 and 2
    Last edited: Oct 8, 2005
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