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Thread: simultaneous equations

  1. #1
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    simultaneous equations

    could you please help me solve this equation

    $\displaystyle x-4y=-2$
    $\displaystyle y=2x-3$
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  2. #2
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    Quote Originally Posted by johnsy123 View Post
    could you please help me solve this equation

    $\displaystyle x-4y=-2$
    $\displaystyle y=2x-3$
    Substitute the value of y into the first equation.

    $\displaystyle x - 4(2x - 3) = -2$

    $\displaystyle x - 8x + 12 = -2$

    $\displaystyle -7x + 12 = -2$

    $\displaystyle -7x = -14$

    $\displaystyle x = 2$.


    Back substitute to find y.

    $\displaystyle y = 2x - 3$

    $\displaystyle y = 2\times 2 - 3$

    $\displaystyle y = 4 - 3$

    $\displaystyle y = 1$.
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