The function of the line (the graph) that passes through the points (x1,y1) and (x2,y2) can be obtained with the formula:
y-y1 = m (x-x1)
m=y1-y2/x1-x2
In our case we need to find the equation that represents the line that passes through the points (-4,3) and (2,-12), which means:
x1=-4, y1=3
x2=2 y2=-12
So, the equation is:
m=3-(-12)/-4=-15/6
y-(-12)=-15/6(x+4)
y+12=-15/6x-60/6x