What two numbers multiply to get -36 and add to get 9

Xy = -36
x + y = 9















       
       
       

    x + y = 9       or        x + y = 9
  12 + y = 9      or       -3 + y = 9
- 12      - 12              + 3       + 3
          y = -3         or          y = 12
(x, y) = (12, -3)    or    (x, y) = (-3, 12)

The two numbers that add up to 9 and multiply to -36 are the numbers -3 and 12.