Find the Area of the Shaded Region $9 x ^ { 2 } + 36 x - 36$

Multiple Choice

Find the area of the shaded region. Write the answer as a polynomial in descending powers of x.
-

A) $9 x ^ { 2 } + 36 x - 36$
B) $9 x ^ { 2 } - 36 x + 36$
C) $9 x ^ { 2 } - 36 x - 36$
D) $9 x ^ { 2 } + 36 x + 36$