Answer:
y = -5
Explanation:
Given two points, we know the slope is
m = (y2-y1)/(x2-x1)
-4 = (-1-y)/(-5--4)
-4 = (-1-y) /(-5+4)
-4 =/(-1-y)/-1
Multiply each side by -1
-1*-4 = (-1-y) /-1*-1
4 = -1-y
Add 1 to each side
4+1 = -1+1-y
5 = -y
Multiply each side by -1
-1*5 = -y*-1
-5 = y