I'm not sure if you're looking for anything more than this, but if you plug in all those values (trail and error) the only one that is successful is (3,-2)
3 + -2 = 1 -3 + -2 = -5
All of those other values are false and do not add up to the correct value.
Ex: (-2,3) -2+3 = 1 (True) - -2+3 = 2+3 = 5 (False, not negative. The - -2 becomes positive.)