Question 371480
<pre>
Add corresponding terms of the two equations and the x-terms
will cancel out automatically since one is 7x and the other is -7x:

 7x + 2y =  10
-7x +  y = -16
--------------
      3y =  -6
      {{{3y/3}}} = {{{-6/3}}}
       y =  -2


Substitute -2 for y in either equation:

    7x + 2y = 10
 7x + 2(-2) = 10
     7x - 4 = 10
         +4   +4
    ------------
     2x     = 14
         {{{2x/2}}} = {{{14/2}}}
          x = 7 
          
Edwin</pre>