What is Evaluation Function?

What is the slope simplify your answer and write it as a proper fraction, improper fraction, or integer

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(x)

Clara schumann is buying bagels for her coworkers, she buys a dozen bagels priced at $5.49 a dozen. the bakery's cost for making the bagels is $2.25 per dozen. what is the markup rate based on selling price on a dozen bagels?