Explain why 7 times x/7 equal x. how does this relate to solving division equation

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?

Do graduates from uf tend to have a higher income than students at fsu, five years after graduation? a random sample of 100 graduates was taken from both schools. let muf be the population mean salary at uf and let mufsu be the population mean salary at fsu. how should we write the alternative hypothesis?

The number of potato chips in a bag is normally distributed with a mean of 71 and a standard deviation of 2. approximately what percent of bags contain between 69 and 73 potato chips? approximately 68% approximately 71% approximately 95% approximately 99.7%