The first three terms of a sequence are 4,8,16

a) Determine the value of r
b) Find the value of S₁₃ (must use and show formula)

Please include work on how to find r on a TI-84 calculator

Which shows one way to determine the factors of  x3  +  5x2  –  6x  –  30 by grouping? x(x2  –  5)  +  6(x2  –  5)x(x2  +  5)  –  6(x2  +  5)x2(x  –  5)  +  6(x  –  5)x2(x  +  5)  –  6(x  +  5)

On saturday morning, calls arrive at ticketmaster at a rate of 108 calls per hour. what is the probability of fewer than three calls in a randomly chosen minute?

What is sin 7x/4 ? i need on this urgent trig