My internet disconnected while I was typing last time so here I am again...
Slope-intercept form: y = mx + b
Finding the slope:
Slope formula: y2-y1/x2-x1
So in this case, plugging the coordinates in...
-3.75 - (-1.75)/ -0.75 - (-3.75)
= 2/3
So the slope is 2/3.
y= 2/3x + b
Now time to find the y-intercept, in which we can plug in one of the coordinates and solve.
Let's plug in... uhh... (-0.75, -3.75).
-3.75 = 2/3 (-0.75) + b
-3.75 = -0.5 + b
b = -3.25
So the equation is y= 2/3x - 3.25.