Write the explicit formula for the geometric sequence.

a1 = -5 a2 = 20 a3 = -80

a. an = -5 • (-4)n

b. an = -5(-4)n-1

c. an = -4(-5)n-1

d. an = -5 • (4)n

Can someone pls ! pls answer all. no explanation needed..

Kendra had twice as much money as kareem. kendra later spent $8 and kareem earned $6. by then,the two had the same amount of money. how much money did each have originally?

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.