Question 697902: what is the answer?twenty one plus the an unknown number is equal to nine decreased by the unknown number. Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! twenty one plus the an unknown number is equal to nine decreased by the unknown number.
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Equation:
Let the unknown number be "x":
21 + x = 9 - x
2x = -12
x = -6
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Cheers,
Stan H.