5/6 is the correct answer!
Might be better if you typed the question
Answer:
The equation is 
The solution of the equation is x=10.
Step-by-step explanation:
The volume of a rectangular prism is found using the formula V = l · w · h, where l is the length, w is the width, and h is the height.
Let x ft be the widht of the stall, then the length of the stall is x+2 ft. If each stall must be 9 ft high, then the volume of the stall is 
The volume of each stall is
then

The width cannot be negative, thus, 
K<4
that should be the answer to your question