Question 601895
  2x+y=3 
 -7x+2y=17.
to solve this multiply 2x+y=3  by -2 to cancel y
so here is the result
 -4x-2y=-6 
 -7x+2y=17
now add both of them the result is 
  -11x=11
    x=-11/11
    x=-1 so this is the value of x.
but if you need to find the value of y substitute x=-1 to either of 2x+y=3 or -7x+2y=17
 for example take 2x+y=3 
          2(-1)+y=3
            -2+y=3
               y=3+2=5