document.write( "Question 102730: sum of the digit of two digit no. is 12. the given no. exceed the no. obtained by interchange the digit by 36. find the given no. \n" ); document.write( "
Algebra.Com's Answer #74713 by ankor@dixie-net.com(22740)\"\" \"About 
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Let x = the 10's digit, and y = the units digit
\n" ); document.write( "Write an equation for each statememt
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\n" ); document.write( "\"sum of the digit of two digit no. is 12.\"
\n" ); document.write( "x + y = 12
\n" ); document.write( "or
\n" ); document.write( "y = 12 - x; we use this for substitution, if needed
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\n" ); document.write( "\"the given no. exceed the no. obtained by interchange the digit by 36.\"
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\n" ); document.write( "Given number: 10x + y
\n" ); document.write( "interchanged number: 10y + x
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\n" ); document.write( "The equation from the given statement:
\n" ); document.write( "10x + y = 10y + x + 36
\n" ); document.write( "Some simple algebra:
\n" ); document.write( "10x - x = 10y - y + 36
\n" ); document.write( "9x = 9y + 36
\n" ); document.write( "Simplify, divide equation by 9
\n" ); document.write( "x = y + 4
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\n" ); document.write( "Substitute (12-x) for y, (from the 1st statement)
\n" ); document.write( "x = (12-x) + 4
\n" ); document.write( "x + x = 12 + 4
\n" ); document.write( "2x = 16
\n" ); document.write( "x = 8
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\n" ); document.write( "y = 12 - 8 = 4
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\n" ); document.write( "Our number is 84:
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\n" ); document.write( "Check it: 84 - 48 = 36
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