you find your slope with the equation
(y2-y1)/(x2-x1)
(-1-2)/ -4-1.5)
(-3)/(-5.5)
.54x is your slope
you then plug that into your equation.
y=mx+b
y=.54x+b
you substitute one of our coordinates.
(-4,-1)
-1=.54(-4)+b
-1=-3.45+b
+3.45
2.45=b
your equation is
y=.54x+2.45
standard form
y-.54x=2.45