X + y = 3. x - y = 7

Question

What two numbers added together equals 3and then when it is subtracted equals 7

 

Answer 1

    x + y = 3
+
    x - y = 7  

   2x = 10 ----> x = 5

  5 + y = 3 ----> y = - 2

5 + (- 2) = 3
 5 - (- 2) = 7