document.write( "Question 753887: Jeff is 7 years older than Marty. The sum of their ages is 71. How old is Marty \n" ); document.write( "
Algebra.Com's Answer #458693 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! Write an equation for each statement \n" ); document.write( ": \n" ); document.write( "Jeff is 7 years older than Marty. \n" ); document.write( "j = m + 7 \n" ); document.write( "or \n" ); document.write( "j - m = 7 \n" ); document.write( ": \n" ); document.write( "The sum of their ages is 71. \n" ); document.write( "j + m = 71 \n" ); document.write( ": \n" ); document.write( "Use elimination here, add the two equations \n" ); document.write( "j - m = 7 \n" ); document.write( "j + m = 71 \n" ); document.write( "------------adding eliminates m, find j \n" ); document.write( "2j = 78 \n" ); document.write( "j = 78/2 \n" ); document.write( "j = 39 is Jeff's age \n" ); document.write( ": \n" ); document.write( " How old is Marty? I'll let you find this \n" ); document.write( " |