Solve these algebraic expression and make it them into one simplified expression (There are two parts)

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

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?