Solve the Problem $A ( x ) = 12 x ^ { 2 } - x$

Multiple Choice

Solve the problem.
-Elissa wants to set up a rectangular dog run in her backyard. She has 20 feet of fencing to work with and wants to use it all. If the dog run is to be x feet long, express the area of the dog run as a function of x.

A) $A ( x ) = 12 x ^ { 2 } - x$
B) $A ( x ) = 9 x - x ^ { 2 }$
C) $A ( x ) = 10 x - x ^ { 2 }$
D) $A ( x ) = 11 x - x ^ { 2 }$