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2 April, 22:38

3x+7 = x-1 does x = - 4?

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  1. 3 April, 00:20
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    Subtract x from both sides:

    (3x - x) + 7 = (x - x) - 1

    3x - x = 2x:

    2x + 7 = (x - x) - 1

    x - x = 0:

    2x + 7 = - 1

    Subtract 7 from both sides:

    2x + (7 - 7) = - 7 - 1

    7 - 7 = 0:

    2x = - 7 - 1

    -7 - 1 = - 8:

    2x = - 8

    Divide both sides by 2:

    2x / 2 = - 8 / 2

    2 / 2 = 1:

    x = - 8 / 2

    The gcd (greatest common denominator) of 8 and 2 is 2:

    -8 / 2 = 2 (-4) / 2x1 = 2/2 x - 4 = - 4

    x = - 4
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