Answer:
The vertex represent the minimum amount of profit
Step-by-step explanation:
Plot the function to better understand the problem
Let
x ----> the number of users in thousands
y ---> the Monthly profit in thousands
using a graphing tool
see the attached figure
we have a vertical parabola open upward
The vertex represent a minimum
In the context of this problem
The vertex represent the minimum amount of profit
In this problem the vertex is the point (0.4,-4)
0.4 represent -----> 0.4(1,000)=400 users
-4=-4(1,000)=-$4,000 (profit negative)
