Answer :
If you multiply second equation with (-1) ;
17x - 2y = 25
-17x - 3y = 5
And sum of this gives ;
- 5y = 30
And -y = 6 which is also y = -6
17x - 2y = 25
-17x - 3y = 5
And sum of this gives ;
- 5y = 30
And -y = 6 which is also y = -6