document.write( "Question 697902: what is the answer?twenty one plus the an unknown number is equal to nine decreased by the unknown number. \n" ); document.write( "
Algebra.Com's Answer #430325 by stanbon(75887)\"\" \"About 
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twenty one plus the an unknown number is equal to nine decreased by the unknown number.
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\n" ); document.write( "Equation:
\n" ); document.write( "Let the unknown number be \"x\":
\n" ); document.write( "21 + x = 9 - x
\n" ); document.write( "2x = -12
\n" ); document.write( "x = -6
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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