Slope intercept form ( y = mx + b)
m is your slope
b is your y intercept
Substitute the point (-1 (x), -8 (y)) into the formula with your slope to find the y intercept
Y = mx + b
-8 = -5 (-1) + b
-8 (-5)= 5 (-5)+ b
-13 = b
So y = -5x -13 is your answer