Answer: Option D
D. ;
Step-by-step explanation:
We know that the cost of preschool is $ 45 per day plus a monthly fee of $ 70.
We also know that a total of $ 880 was paid last month
To write an equation that represents this situation, let us call "d" the number of days that Barry attends school
So the cost was:
Now we solve the equation for the variable d
Therefore answer is the option D
Answer:
cm
Step-by-step explanation:
The volume of the box is:
V = height * length * width
V = x*(66 - 2*x)*(90 - 2*x)
V = (66*x - 2*x^2)*(90 - 2*x)
V = 5940*x - 132*x^2 - 180*x^2 + 4*x^3
V = 4*x^3 - 312*x^2 + 5940*x
where x is the length of the sides of the squares, in cm.
The mathematical problem is :
Maximize: V = 4*x^3 - 312*x^2 + 5940*x
subject to:
x > 0
2*x < 66 <=> x < 33
In the maximum, the first derivative of V, dV/dx, is equal to zero
dV/dx = 12*x^2 - 624*x + 5940
From quadratic formula
But , then is not the correct answer.