document.write( "Question 624491: The sum of the digits of a 2-digit number is 9. The digits are reversed and the new number is substracted from the original numbe, to get 45. Find the original number.
\n" ); document.write( "(to be solved in Linear equation with one variable) \n" ); document.write( "
Algebra.Com's Answer #392777 by meghraj(2)\"\" \"About 
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Let the first digit be x and the second digit be y.
\n" ); document.write( "then by question,\r
\n" ); document.write( "\n" ); document.write( " x + y = 9
\n" ); document.write( "=> y = 9 - x ------- eq 1\r
\n" ); document.write( "\n" ); document.write( "Again,
\n" ); document.write( "Since the number is 10x+y when it is revered then the number becomes 10y + x.\r
\n" ); document.write( "\n" ); document.write( "Therefore, we get by question
\n" ); document.write( "=> 10x + y -(10y + x) = 45
\n" ); document.write( "=> 10x + y - 10y - x = 45
\n" ); document.write( "=> 9x -9y = 45
\n" ); document.write( "=> x - y = 5
\n" ); document.write( "=> x = 5+y
\n" ); document.write( "=> x = 5 + (9-x) -----frm eq 1
\n" ); document.write( "=> x = 5 + 9 - x
\n" ); document.write( "=> 2x = 14
\n" ); document.write( "=> x = 7\r
\n" ); document.write( "\n" ); document.write( "Now, eq 1
\n" ); document.write( " y = 9 - x
\n" ); document.write( "=> y = 9 - 7
\n" ); document.write( "=> y = 2\r
\n" ); document.write( "\n" ); document.write( "Therefore the number is 72\r
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