The explicit formula for the geometric sequence -1/9, 1/3, -1, 3, -9, ... is -1/9(-3)^x-1 . What is the common ratio and recursive formula for this sequence

The perimeter of a movie screen is 54 meters. the screen is 18 meters wide. how tall is it?

Amountain climber starts a climb at an elevation of 453 feet above sea level at his first rest stop he has climbed 162 feet and by his second rest stop he has climbed another 207 feet its getting late in the day so the climber starts his way down if the climber desends 285 feet how much does he need to ascend or descend to return to the original starting point

1. if events a and b are non-overlapping events, how do you find the probability that one or the other occurs? 2. what does it mean if p(a or b) equals 1?