Can someone me with this and show the work

Width to give maximum area is 12 feet. Maximum area is 144 square feet.

Step-by-step explanation:

Given:

Width is given as .

Area of the rectangular pen is given as,

For maximum area, the derivative of area with respect to must be 0. So,

Therefore, for maximum area, the width should be 12 feet.

Now, plug in 12 ft for in the expression for area to calculate maximum area. This gives,

Maximum area, , is given as:

Therefore, the maximum area is 144 square feet.

step-by-step explanation:

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50