Math

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So I've been working on solving this system by addition/subtraction and I just can't get the right answer. Her is the system of equations I was given to solve by add/sub:

3x – y = –12
x + 2y = –18

  • Math -

    double the first:
    6x - 2y = -24
    x + 2y = -18
    add them:
    7x = -42
    x = -6

    back into the second:
    -6 + 2y = -18
    2y = -12
    y = -6

    x = -6 , y = -6

  • Math -

    solve the system by substitution
    6x+2y=-18
    -x+5y=19

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