what is the answer to this

x=-3, y=9

y = -x + 6

y = -6x – 9     set both equations equal

 -x + 6  = -6x – 9      add 9, x  to both sides

15 = - 5x           divide both sides by - 5

-3  = x       sub into either equation to find y

y = - [ -3] + 6   = 9

So  {x , y}  =  {-3, 9 }