Answer:
[tex]C(x) = 45x + 75\\\text{where x is the width of rectangular pen}[/tex]
Step-by-step explanation:
We are given the following in the question:
The length of the pen will be 5 feet more than twice as long as the width of the pen.
Let y be the length and x be the width. Thus, we can write:
[tex]y = 2x +5[/tex]
Fencing = Perimeter of rectangular pen
[tex]\text{Perimeter of rectangle} = 2(\text{length} + \text{width})\\ P = 2(y+x)\\P=2(2x+5+x)\\P= 2(3x+5)\\P = (6x + 10)\text{ feet}[/tex]
The cost of the pen will be $7.50 per foot of fencing.
Total Cost of fencing =
[tex]\text{Cost of fencing}\times \text{Perimeter}\\C(x) = 7.50\times (6x+10)\\C(x) = 45x + 75\\\text{where x is the width of rectangular pen}[/tex]
is the required cost function.