document.write( "Question 113239: 3x + y = 2 and 2x-y=3 \n" ); document.write( "
Algebra.Com's Answer #82407 by bucky(2189)![]() ![]() ![]() You can put this solution on YOUR website! Given the two equations: \n" ); document.write( ". \n" ); document.write( "3x + y = 2 \n" ); document.write( "2x - y = 3 \n" ); document.write( ". \n" ); document.write( "This pair of equations is \"nicely\" arranged for solving by variable elimination because \n" ); document.write( "one of the terms in the top equation [that term is +y] is equal but with the opposite \n" ); document.write( "sign to the corresponding term in the bottom equation [that term is -y]. If you add these \n" ); document.write( "two equations vertically, the y-column will disappear because +y added to -y cancels \n" ); document.write( "out. \n" ); document.write( ". \n" ); document.write( "In the x column the 3x adds to the 2x and equals 5x. As we mentioned, in the y column the \n" ); document.write( "+y and the -y sum to zero and therefore are gone. And on the other side of the equal sign \n" ); document.write( "the +2 and the +3 add to 5. So, after adding the two equations vertically you are left \n" ); document.write( "with 5x = 5. You can solve this equation for x by dividing both sides of this equation by \n" ); document.write( "5 (the multiplier of the x) and you get: \n" ); document.write( ". \n" ); document.write( "x = 5/5 = 1 \n" ); document.write( ". \n" ); document.write( "So you now know that x = 1 \n" ); document.write( ". \n" ); document.write( "You can then go back to either one of the two equations you were given and replace x by 1 \n" ); document.write( "in that equation and then solve for y. Let's go back to the first equation: \n" ); document.write( ". \n" ); document.write( "3x + y = 2 \n" ); document.write( ". \n" ); document.write( "replace x by 1 and the equation becomes: \n" ); document.write( ". \n" ); document.write( "3(1) + y = 2 \n" ); document.write( ". \n" ); document.write( "do the multiplication of 3 times 1 and the equation reduces to: \n" ); document.write( ". \n" ); document.write( "3 + y = 2 \n" ); document.write( ". \n" ); document.write( "Get rid of the 3 on the left side by subtracting 3 from both sides of the equation to \n" ); document.write( "reach the solution: \n" ); document.write( ". \n" ); document.write( "y = 2 - 3 = -1 \n" ); document.write( ". \n" ); document.write( "So the solution to this problem is x = 1 and y = -1 \n" ); document.write( ". \n" ); document.write( "Hope this helps you to understand the problem a little better. \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( " |