document.write( "Question 992164: Please help me solve this word problem leading to quadractic
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document.write( "The sum of the digits of a two-digit number is 14. The tens digit is the square of a number which is 2 less than the units digit. Find the two-digit number. \n" );
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Algebra.Com's Answer #611839 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! let t = the ten's digit \n" ); document.write( "let u = the units \n" ); document.write( ": \n" ); document.write( "Write an equation for each statement \n" ); document.write( ": \n" ); document.write( "The sum of the digits of a two-digit number is 14. \n" ); document.write( "t + u = 14 \n" ); document.write( "or \n" ); document.write( "t = (14-u); use this form for substitution \n" ); document.write( ": \n" ); document.write( " The tens digit is the square of a number which is 2 less than the units digit. \n" ); document.write( "t = (u-2)^2 \n" ); document.write( "FOIL (u-2)(u-2) \n" ); document.write( "t = u^2 - 4u + 4 \n" ); document.write( "Replace t with (14-u) \n" ); document.write( "14 - u = u^2 - 4u + 4 \n" ); document.write( "0 = u^2 - 4u + u + 4 - 14 \n" ); document.write( "A quadratic equation \n" ); document.write( "u^2 - 3u - 10 = 0 \n" ); document.write( "Factors to \n" ); document.write( "(u-5)(u+2) = 0 \n" ); document.write( "The positive solution is what we want here \n" ); document.write( "u = 5 \n" ); document.write( "then \n" ); document.write( "t = 14 - 5 \n" ); document.write( " t = 9 \n" ); document.write( ": \n" ); document.write( " Find the two-digit number. 95 \n" ); document.write( ": \n" ); document.write( "; \n" ); document.write( "we can confirm this, in the 2nd statement \n" ); document.write( "\"The tens digit is the square of a number which is 2 less than the units digit.\" \n" ); document.write( "9 = (5-2)^2 \n" ); document.write( "9 = 3^2 \n" ); document.write( " |