Answer:
160 units.
Step-by-step explanation:
In order to find the minimum cost, we need to find the vertex of the equation since it is the lowest point of the graph. To find the vertex, we use the following equation.
x = -b/2a
In this equation, a is the coefficient of x^2 and b is the coefficient of x. So we plug in and solve.
x = -b/2a
x = -(-80)/2(.25)
x = 80/.5
x = 160
