The slope of this line is
-5 - 3 -8
m = ----------- = ----------
4-(-1) 5
Then use the point-slope format to find the equation of this line.
y-3 = (-8/5)(x-(-1)), or y - 3 = (-8/5)( x + 1) (answer)
This could be re-written in other forms, such as the slope-intercept form.