Find f '(x) for f of x equals the square root of the quantity sine of 8 times x

see attached for the problem and answers

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items

You paid 28.00 for 8 gallons of gasoline. how much would you pay for 15 gallons of gasoline?

What are the solutions of the system? solve by graphing. y = x^2 + 3x + 2 y = 2x + 2