You would want to find the average rate of change to find how much y = ?x is. So we would take two coordinates, whichever ones : (-4, -6) and (-2, -3) and find the average rate of change. The following is the formula:

: Which, when the points are applies, would make it :

: And simplified, that would become :

: and when this fraction is converted into a decimal, it would be 1.5.
y = 1.5x