Which relations are functions? choose all answers that are correct. a. x –1 1 3 3 y 2 3 4 5 b. a parabola, opening down, is graphed on a coordinate grid. the parabola goes through point 0, 5, point 2, 1, and point negative 2, 1. c. {(−2, 4), (−1, 2), (1, 2), (3, 5)} d. a set of points are plotted on a coordinate grid. the points include point negative 3,3, point negative 1, 1, point negative 1, 6, point 1, 4, point 2, 1, and point 3, 2.

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.