Is the fith power of negative 18 negative or positive

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

Students are given 3 minutes for each multiple-choice question and 5 minutes for each free-response question on a test. there are 15 questions on the test, and students are given 51 minutes to take it. how many multiple-choice questions are on the test?

Abowl contained 270 starbursts of all different colors. if the probability of picking a yellow is 1/9, then how many yellow starbursts are in the bowl ? ?