document.write( "Question 32011This question is from textbook Beginning Algebra
\n" ); document.write( ": A number consists of two digits whose sum is five. When the digits are reversed, the number is increased by nine. Find the number. \n" ); document.write( "
Algebra.Com's Answer #18552 by mbarugel(146)\"\" \"About 
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\n" ); document.write( "Let's call X to the first digit and Y to the second digit. The two digit number is then written as:\r
\n" ); document.write( "\n" ); document.write( "\"10X+%2B+Y\"\r
\n" ); document.write( "\n" ); document.write( "For example, if the digits are 3 and 7 (the number is 37), then the above expression yields:\r
\n" ); document.write( "\n" ); document.write( "\"10%2A3+%2B+7+=+37\"\r
\n" ); document.write( "\n" ); document.write( "We know that the sum of the digits is 5, so we get the equation:
\n" ); document.write( "\"X%2BY=5\"
\n" ); document.write( "We also know that when we reverse the number, it increases by 9. This implies that:
\n" ); document.write( "\"10Y%2BX+=+10X%2BY%2B9\"
\n" ); document.write( "\"9Y+-+9X+=+9\"
\n" ); document.write( "\"Y+-+X+=+1\"\r
\n" ); document.write( "\n" ); document.write( "We can isolate Y from this equation:
\n" ); document.write( "\"Y+=+1+%2B+X\"
\n" ); document.write( "And replace it in the previous one:
\n" ); document.write( "\"X%2B1%2BX+=+5\"
\n" ); document.write( "Now solve for X:
\n" ); document.write( "\"1%2B2X+=+5\"
\n" ); document.write( "\"X+=+2\"\r
\n" ); document.write( "\n" ); document.write( "Since the sum is 5, then Y must be 3. Therefore, the number is 23.\r
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\n" ); document.write( "\n" ); document.write( "I hope this helps!
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