document.write( "Question 946177: A two digit number is 54 more than the number formed by interchanging the digits the difference between the product and the sum of the digits is 15. Find the number \n" ); document.write( "
Algebra.Com's Answer #577334 by ankor@dixie-net.com(22740) You can put this solution on YOUR website! let a = the 10's digit \n" ); document.write( "let b = the units \n" ); document.write( "then \n" ); document.write( "10a + b = the number \n" ); document.write( "and \n" ); document.write( "10b + a = the number with digits reversed \n" ); document.write( ": \n" ); document.write( "A two digit number is 54 more than the number formed by interchanging the digits \n" ); document.write( "10a + b = 10b + a + 54 \n" ); document.write( "10a - a = 10b - b + 54 \n" ); document.write( "9a = 9b + 54 \n" ); document.write( "simplify, divide by 9 \n" ); document.write( "a = b + 6 \n" ); document.write( ": \n" ); document.write( " the difference between the product and the sum of the digits is 15. \n" ); document.write( "ab - (a+b) = 15 \n" ); document.write( "replace a with (b+6) \n" ); document.write( "b(b+6) - ((b+6)+b) = 15 \n" ); document.write( "b^2 + 6b - (2b + 6) = 15 \n" ); document.write( "combine like terms \n" ); document.write( "b^2 + 6b - 2b - 6 - 15 = 0 \n" ); document.write( "b^2 + 4b - 21 = 0 \n" ); document.write( "Factors to \n" ); document.write( "(b + 7)(b - 3) = 0 \n" ); document.write( "The positive solution is what we want here \n" ); document.write( "b = 3 \n" ); document.write( "Find a \n" ); document.write( "a = 3 + 6 \n" ); document.write( "a = 9 \n" ); document.write( ": \n" ); document.write( "93 is the number. \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check this in the statement: \n" ); document.write( "\"A two digit number is 54 more than the number formed by interchanging the digits \" \n" ); document.write( "93 = 39 + 54 \n" ); document.write( ": \n" ); document.write( "You can check it in the other statement \n" ); document.write( "\" the difference between the product and the sum of the digits is 15. \n" ); document.write( " |