The first step is finding the slope of the equation -8x + 10y = 40.
To do so, let's put this equation in the slope-intercept form: y = mx + b, where m is the slope.
So we have:

Then, since the line we want is perpendicular to this given line, their slopes have the following relation:

So, calculating the slope of the line, we have:

Finally, our equation has the point (-32, -12) as a solution, so we have:

So our equation is y = (-5/4)x - 52