In which quadrant is P(x,y) located if xy < 0 and x + y < 0?
For xy > 0, I figured that for this to be true, both x and y must be positive values.
In other words, x and y cannot be 0 and negative.
For x + y < 0, one of the variables must be bigger than the other and negative.
I don't know where to go with this question in order to find the quadrant.