document.write( "Question 1080008: Sum of two digits of a 2-digit number is 7. If the digits are reversed, the new number so formed decrease by 27 . find the number \n" ); document.write( "
Algebra.Com's Answer #694251 by ankor@dixie-net.com(22740)\"\" \"About 
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let a = the 10's digit
\n" ); document.write( "let b = the units
\n" ); document.write( ":
\n" ); document.write( "10a + b = the number
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\n" ); document.write( "Sum of two digits of a 2-digit number is 7.
\n" ); document.write( "a + b = 7
\n" ); document.write( " If the digits are reversed, the new number so formed decrease by 27 .
\n" ); document.write( "10a + b = 10b + a + 27
\n" ); document.write( "10a - a = 10 - b + 27
\n" ); document.write( "9a = 9b + 27
\n" ); document.write( "simplify, divide by 9
\n" ); document.write( "a = b + 3
\n" ); document.write( "a - b = 3
\n" ); document.write( " find the number
\n" ); document.write( "Use elimination
\n" ); document.write( "a + b = 7
\n" ); document.write( "a - b = 3
\n" ); document.write( "-----------Addition eliminates b, find a
\n" ); document.write( "2a = 10
\n" ); document.write( "a = 5 is the first digit
\n" ); document.write( "you can do the rest \n" ); document.write( "
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