A cleaning company charges \( \$ 180 \) for each office it cleans. The fixed monthly cost of \( \$ 480 \) for the company includes telephone service and the depreciation on cleaning equipment and a van. The variable cost is \( \$ 60 \) per office and includes labor, gasoline, and cleaning supplies. (a) Write a linear cost function representing the cost \( C ( x ) \) (in \( \$ \) ) to clean \( x \) offices per month. (b) Write a linear revenue function representing the revenue \( R ( x ) \) (in \( \$ \) ) for cleaning \( x \) offices per month. (c) Determine the number of offices to be cleaned per month for the company to break even. (d) If \( 21 \) offices are cleaned, will the company make money or lose money?