Use the linear combination method to solve the system of equations. Explain each step of your solution 3x - 8y= 7 x + 2y= -7?

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  • 2 weeks ago

    3x - 8y = 7

    x + 2y = -7

    7x = -21

    x = -3, y = -2

  • DWRead
    Lv 7
    2 weeks ago

    Gaussian Elimination:

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  • 2 weeks ago

    We used to call this "elimination method".  You want to get one of your variables to have opposite coefficients in each equation so when  you add the equations together it cancels out one of the variables:

    3x - 8y = 7

    x + 2y = -7

    I'll multiply the second equation by 4 so the coefficients of y become opposites:

    3x - 8y = 7

    4x + 8y = -28

    --------------------  Add the equations together to get:

    7x = -21

    Now we can solve for x:

    x = -3

    Now we can substitute this value into either equation and solve for y:

    x + 2y = -7

    -3 + 2y = -7

    2y = -4

    y = -2

    The solution to your system of equations is:

    x = -3 and y = -2

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