A book seller bought 80 copies of books at 3.50 per copy . He sold each of them at 4.20 , find the total price and profit cost price

For the function, f(x) = -5x 2, find f(-4).

Adecibel is a logarithmic unit that can be used to measure the intensity of a sound. the function y = 10logx gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity. the reference intensity is generally set at the threshold of hearing. use the graphing utility to graph the decibel function.a whisper has a sound intensity of 30 decibels. use your graph to you complete the following statement. the sound intensity of a whisper is times the reference intensity.

Find the length of the normal and the angle it makes with the positive x-axis. (see pictured below)