Your line in slope-intercept becomes:
y = 1/5x -1
A line that is perpendicular to that has the negative reciprocal slope of the given slope which becomes:
-5
Place the given point in the y=mx+b for x and y. to find b:
0=-5(-1) + b
0=5 +b
-5 = b
Therefore, your equation/answer is:
y = -5x -5