document.write( "Question 989101: When you reverse the digits in a certain two-digit number you decrease its value by 9. What is the number if the sum of its digits is 13?
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Algebra.Com's Answer #609529 by josmiceli(19441) $\"\"$ $\"About$

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Let the units digit = $\"+b+\"$
\n" ); document.write( "Let the tens digit = $\"+a+\"$
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\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+a+%2B+b+=+13+\"$
\n" ); document.write( "(2) $\"+10a+%2B+b+=+10b+%2B+a+%2B+9+\"$
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\n" ); document.write( "(2) $\"+9a+-+9b+=+9+\"$
\n" ); document.write( "(2) $\"+a+-+b+=+1+\"$
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\n" ); document.write( "Add (1) and (2)
\n" ); document.write( "(1) $\"+a+%2B+b+=+13+\"$
\n" ); document.write( "(2) $\"+a+-+b+=+1+\"$
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\n" ); document.write( " $\"+2a+=+14+\"$
\n" ); document.write( " $\"+a+=+7+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+a+-+b+=+1+\"$
\n" ); document.write( "(2) $\"+b+=+a+-+1+\"$
\n" ); document.write( "(2) $\"+b+=+7+-+1+\"$
\n" ); document.write( "(2) $\"+b+=+6+\"$
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\n" ); document.write( "The number is 76
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\n" ); document.write( "check:
\n" ); document.write( "Reverse the digits: 67
\n" ); document.write( " $\"+76+-+67+=+9+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+7+%2B+6+=+13+\"$
\n" ); document.write( "OK \n" ); document.write( "

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