Derek has $20 to spend on used books. Hard cover books cost $5 each and paperbacks cost $2 each. Complete the equation which determines the number x of hardcover books and the number y of paperback books he can buy. What are the possible combinations of books that Derek can buy? Select all that apply. A. (-2,15)
B. (0,10)
C. ( 2,5)
D. (3,5/2)

Janet drove 300 miles in 4.5 hours. write an equation to find the rate at which she was traveling

Analyze the diagram below and complete the instructions that follow. how to find tan

Awavelength of 610 nm was found to be the most intense wavelength emitted by copper. answer the following questions about this wavelength of light. a) what is this wavelength in cm? b) what is the frequency that corresponds to this wavelength? c) what is the energy of light of this wavelength? d) what is the wavenumber corresponding to this wavelength?