Add the equations,just the way they appear there.
-- Add the top 'x' to the bottom 'x'. Write the sum under the 'x's.
-- Add the '+y' and the '-y'. Write the sum under the 'y's.
-- Add the '2' and the '4'. Write the sum under them, with n " = " sign
before it.
You should now have an equation with only 'x' in it and no 'y'.
You can easily solve that one and find out the value of 'x'.
Once you know the value of 'x', go back to either one of the original
equations, and plug the number-value of 'x' in place of 'x'.
You'll then have an equation with only 'y' in it and no 'x'.
You can easily solve that one and find out the value of 'y'.
