Write down any rational number between 4 and 6

Which expressions are equivalent to the one below? check all that apply. 25x/5x a. 5x b. 5 c. 5x•5x/5x d. 25x e. (25/5)^x f. (25-5)^x

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?

Can someone me with my math problem pls my teacher is on my back about this