document.write( "Question 211397: if 6 is added to a number and then subtracted from the same number, the product of the sum and the difference is 189. What is the number?
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Algebra.Com's Answer #159759 by Alan3354(69443)\"\" \"About 
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if 6 is added to a number and then subtracted from the same number, the product of the sum and the difference is 189. What is the number?
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\n" ); document.write( "The quick and easy way:
\n" ); document.write( "189 + 6^2 = 225
\n" ); document.write( "225 is the square of the original number - sqrt(225) = ±15
\n" ); document.write( "9*21 = 189
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\n" ); document.write( "The hard way:
\n" ); document.write( "(n-6)*(n+6) = 189
\n" ); document.write( "n^2 - 36 = 189
\n" ); document.write( "n^2 = 225
\n" ); document.write( "n = 15 (and -15)
\n" ); document.write( "Not much difference in the 2 methods \n" ); document.write( "
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