Arectangular schoolyard is to be fenced in using the wall of the school for one side and 150 meters of fencing for the other three sides. the area a(x) in square meters of the schoolyard is a function of the length x in meters of each of the sides perpendicular to the school wall.
a. write an expression for a(x).
b. what is the area of the schoolyard when x=40?
c. what is a reasonable domain for a in this context?

The area of a shape is the amount of space on it.

The perimeter of the schoolyard is given as: 150

So, we have:

Substitute 150 for P

Make y the subject

The area (A) of a schoolyard is:

Substitute

Express as a function

The area when x = 40, is:

x cannot be less than 0.

Also, we have:

Set to 0

Rewrite as:

Divide both sides by -2

So, the reasonable domain is:

Read more about area functions at:

link

Part 1) The expression is

Part 2) The area of the schoolyard when x=40 m is A=2,800 m^2

Part 3) The domain is all real numbers greater than zero and less than 75 meters

Step-by-step explanation:

Part 1) Write an expression for A(x)

Let

x -----> the length of the rectangular schoolyard

y ---> the width of the rectangular schoolyard

we know that

The perimeter of the fencing (using the wall of the school for one side) is

so

-----> equation A

The area of the rectangular schoolyard is

---> equation B

substitute equation A in equation B

Convert to function notation

Part 2) What is the area of the schoolyard when x=40?

For x=40 m

substitute in the expression of Part 1) and solve for A

Part 3) What is a reasonable domain for A(x) in this context

we know that

A represent the area of the rectangular schoolyard

x represent the length of of the rectangular schoolyard

we have

This is a vertical parabola open downward

The vertex is a maximum

The x-coordinate of the vertex represent the length for the maximum area

The y-coordinate of the vertex represent the maximum area

The vertex is the point (37.5, 2812.5)

using a graphing tool, see the attached figure

therefore

The maximum area is 2,812.5 m^2

The x-intercepts are x=0 m and x=75 m

The domain for A is the interval -----> (0, 75)

All real numbers greater than zero and less than 75 meters

why can't you?

step-by-step explanation:

if the probability is 1/12, 75 people will receive a $25 gift card

step-by-step explanation: