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Define x :
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Let one of the numbers be x.
1st number = x
2nd number = x + 2
3rd number = x + 4
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Construct the equation :
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The 3 numbers add up to -9.
x + x + 2 + x + 4 = -9
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Solve x :
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x + x + 2 + x + 4 = -9
3x + 6 = -9
3x = -9 -6
3x = -15
x = -5
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Find the numbers :
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1st number = x = -5
2nd number = x + 2 = -5 + 2 = -3
3rd number = x + 4 = -5 + 4 = -1
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Answer: The 3 numbers are -5, -3, -1
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