The relationship to go from Cartesian coordinates to polar coordinates is given by the following equations:
x = r * cos(theta)
y = r * sin(theta)
Since the coordinates we are given are just variables that can take any value, we'll have to work with that. Thankfully, that means we can just plug in these equations to get polar coordinates!
(-x, y) becomes
(-(r * cos(theta)), r * sin(theta))
