Consider the set of all points in the coordinate plane for which one of the coordinates is exactly negative three times the other. If we were to plot all such points, into how many regions would the resulting graph split up the plane?
We would have the following lines
y = -3x
x = -3y
These split the plane into 4 regions
See the graph, here : https://www.desmos.com/calculator/pekveaesjs