document.write( "Question 641139: the sum of a certain number and a second number is -42. the first number minus the second is 52. find the numbers. \n" ); document.write( "
Algebra.Com's Answer #403545 by josh_jordan(263)![]() ![]() You can put this solution on YOUR website! To solve, let's turn each of the sentences into an equation. The first sentence says that the sum of a certain number and a second number is -42. In other words:\r \n" ); document.write( "\n" ); document.write( "x + y = -42 (where x and y each represent one of those numbers)\r \n" ); document.write( "\n" ); document.write( "The second sentence says that the first number minus the second number is 52. In other words:\r \n" ); document.write( "\n" ); document.write( "x - y = 52\r \n" ); document.write( "\n" ); document.write( "These two equations form a system of linear equations. We can find x and y by adding these two equations together. So,\r \n" ); document.write( "\n" ); document.write( "x + y + x - y = -42 + 52\r \n" ); document.write( "\n" ); document.write( "Leaving us with\r \n" ); document.write( "\n" ); document.write( "2x = 10\r \n" ); document.write( "\n" ); document.write( "Dividing both sides by 2 will leave us with x:\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 5\r \n" ); document.write( "\n" ); document.write( "Now, to solve for y, just replace x in either equation, with 5. Let's use the first equation: x + y = -42:\r \n" ); document.write( "\n" ); document.write( "5 + y = -42\r \n" ); document.write( "\n" ); document.write( "Subtract both sides by 5:\r \n" ); document.write( "\n" ); document.write( "5 - 5 + y = -42 - 5, so\r \n" ); document.write( "\n" ); document.write( "y = -47\r \n" ); document.write( "\n" ); document.write( "FINAL ANSWER: 5 and -47 are the two numbers \n" ); document.write( " |