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-   -   Algebra: solve by elimination (https://www.askmehelpdesk.com/showthread.php?t=306383)

  • Jan 20, 2009, 03:50 PM
    TysonBrown
    Algebra: solve by elimination
    I don't know what to get rid of!

    -2x+3y=14
    x-4y=-12



    Help me!
  • Jan 20, 2009, 05:09 PM
    ROLCAM

    -2x+3y=14
    x-4y=-12
    _______________________
    -2x+3y=14
    2x-8y = -24
    _____________________
    eliminate the x's you get:

    +3y = 14
    -8y = -24

    so
    -5y = -10

    y = 2

    x-4y=-12
    x = 4y-12
    x=8 -12
    x = -4

    x = -4 and y = 2
  • Jan 20, 2009, 07:17 PM
    sarnian
    Rolcam : the student should be helped with an explanation to understand the question and procedure, and answer it himself/herself.

    My advice to him/her would be :

    Select either x or y, and substitute the value of it in the other term.
    The easiest way here seems using x for that.

    a) -2x+3y=14
    b) x-4y=-12

    We know the value of -2x as in term a) is stated : -2x + 4y = 12 , so -2x =...

    We know the value of x as in term b) is stated : x - 4y = -12 , so x =...

    Divide the value of -2x in term a) with -2 (divide everything with -2), and you get : x =...

    Now substitute the value of x from term a) into term b) , and solve y !

    This board is called "Homework Help", and not "Do their homework !!!"
  • Jan 20, 2009, 07:24 PM
    shebester

    Rolcam you are amazing thanks

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