A Rectangular Swimming Pool Has a Concrete Walk Around It $A = x ^ { 2 } + 1800 x + 900$

Multiple Choice

A rectangular swimming pool has a concrete walk around it of width x. The pool has a length l = 36 feet and a width w = 25 feet (see figure) . Find an expression representing the combined area A of the pool And the walk. Simplify the result.

A) $A = x ^ { 2 } + 1800 x + 900$
B) $A = 900 + x ^ { 2 }$
C) $A = 4 x ^ { 2 } + 122 x + 900$
D) $A = x ^ { 2 } + 900$