Answer:
5/4
Step-by-step explanation:
If a line is perpendicular to another, its slopes multiply up to -1.
So, we should write x•-4/5=-1
-4x/5=-1
x=-1•(-5/4)
x=5/4
So, we have y=5/4x+b
Slope is just the value before the x, which in this case is 5/4/.
