8. [-/0.9 Points] DETAILS TANAPMATH7 9.6.054. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Find dy/du, du/dx, and dy/dx when y and u are defined as follows. y = - and u = Vx+7 ay = du du dx dy dx 10. [-/0.9 Points] DETAILS TANAPMATH7 9.6.070. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Selling Price of DVD Recorders The rise of digital video and the improvement to the DVD format are some of the reason why the average selling price of standalone DVD recorders has dropped in the coming years. The function A(t) = 699 (t + 1)0.94 (0 s t s 13) gives the projected average selling price (in dollars) of stand-alone DVD recorders in year t, where t = 0 corresponds to the beginning of 2002.+ How fast was the average selling price of standalone DVD recorders falling at the beginning of 2002? How fast was it falling at the beginning of 2015? (Round your answers to the nearest cent.) 2002 per year 2015 $ per year 11. [-/1 Points] DETAILS TANAPMATH7 9.6.076. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Effect of Luxury Tax on Consumption Government economists of a developing country determined that the purchase imported perfume is related to a proposed "luxury tax" by the following formula where N(x) measures the percentage of norma consumption of perfume when a "luxury tax" of x% is imposed on it. N(x) = V 10,000 - 40x - 0.02x2 (0 S x S 200) Find the rate of change of N(x) for taxes of 50%, 100%, and 120%. (Round your answers to three decimal places.) 50% tax consumption/percentage increase in tax 100% tax consumption/percentage increase in tax 120% tax consumption/percentage increase in tax