For this problem I would change:
2x + 3y = 25 into 
-2x - 3y = -25 
Then, I would add up both equations by lining them up top of another.  
   5x + 3y = 31
+ -2x - 3y = -25
3x = 6 
x = 2
Now that you have x, solve for y. 
5x + 3y = 31
5(2) + 3y = 31 
10 + 3y = 31
3y = 21 
y = 7 
So, x is 2 and y is 7. 
Check to see if the values are correct by plugging them into the other equation.  
2x + 3y = 25
2(2) + 3(7) = 25
4 + 21 = 25
25 = 25 
Since the values are correct, the solution to this problem is A (2, 7).