document.write( "Question 462311: two numbers total 78 and have a difference of 6 \n" ); document.write( "
Algebra.Com's Answer #316939 by math-vortex(648)![]() ![]() You can put this solution on YOUR website! Two numbers total 78 and have a difference of 6. I presume that you want to know what the two numbers are. \n" ); document.write( "======================== \n" ); document.write( ". \n" ); document.write( "Let \n" ); document.write( "x = the first number \n" ); document.write( "y = the second number \n" ); document.write( ". \n" ); document.write( "The sum of the two numbers is 78. Using algebra, we write the equation, \n" ); document.write( "x + y = 78 \n" ); document.write( ". \n" ); document.write( "The difference between the number is 6. Using algebra, we write, \n" ); document.write( "x - y = 6 \n" ); document.write( ". \n" ); document.write( "Now we have a system of two equations in two variables. The system lends itself nicely to solving by elimination. Add the two equations together. \n" ); document.write( ". \n" ); document.write( "x + y = 78 \n" ); document.write( "x - y = 6 \n" ); document.write( "---------- \n" ); document.write( "2x + 0 = 84 \n" ); document.write( "x = 42 \n" ); document.write( ". \n" ); document.write( "Now we know that the first number is 42. Since the difference between the two numbers is 6, the second number is 42 - 6 = 36. \n" ); document.write( ". \n" ); document.write( "The sum of 42 and 36 is 78, so these are our two numbers. \n" ); document.write( ". \n" ); document.write( "-------------- \n" ); document.write( "I solved this using a system of linear equations. You can also solve it by writing an expression for the 2nd number in terms of x. \n" ); document.write( ". \n" ); document.write( "Let \n" ); document.write( "x = 1st number \n" ); document.write( "x - 6 = 2nd number \n" ); document.write( ". \n" ); document.write( "The sum of the two numbers is 78, so \n" ); document.write( "x + (x-6) = 78 \n" ); document.write( ". \n" ); document.write( "Now solve for x, and proceed as I did above. \n" ); document.write( ". \n" ); document.write( "hope this helps! \n" ); document.write( ". \n" ); document.write( "Ms.Figgy \n" ); document.write( "math.in.the.vortex \n" ); document.write( " \n" ); document.write( " |