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-   -   Substitution Method (https://www.askmehelpdesk.com/showthread.php?t=275369)

  • Oct 30, 2008, 11:43 AM
    nicmike04
    Substitution Method
    Thank you for answering my question, but it really did not help I will give you an example of the problem that I have

    x+2y=1
    3x-y=10

    I cannot figure out how to solve this at all. I have used all of the Google search engines to try to figure it out and it is not helping..

    Someone please help me!

    Thank you,
    Nicole
  • Oct 31, 2008, 01:57 AM
    Unknown008

    Substitution is a method where you have to 'replace' one variable into an equation so that only one variable is left. So, in your question;

    x+2y=1
    3x-y=10

    There are numerous ways to solve this problem with substitution. Let's do the simplest.

    x+2y=1

    Make x subject of formula,

    x = 1-2y

    Now, you, in a way, 'know' what x is. Since you 'know', plug it in your second equation!

    3(1-2y)-y=10

    You see? I replaced 'x' by its equal equation, that is '1-2y'. Now, you can solve the equation, find 'y' and solve for x using the first equation!

    Hope it helped you, post back if you need more explanation:). However I think I was clear enough.
  • Jan 6, 2009, 09:38 PM
    mariarosamaripo
    2x-3=-y
    3x+5y=2
  • Jan 6, 2009, 09:42 PM
    mariarosamaripo
    I need help with substitution
    :confused:
  • Jan 8, 2009, 01:21 AM
    Unknown008

    Next time Maria, start a new thread for your question.

    Substitution is a simple way to solve equations. You only need to choose a variable, and replace it in the other equation.

    For example, make 'y' in 2x-3=-y, the subject of that formula.

    Post back, then we'll go on.
  • Jan 8, 2009, 01:28 AM
    juhi2011

    3(1-2y)-y=10
    the equation becomes a linear equation, use your brain in the same direction to get the answer, I hope this will help you

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