Factor completely. x^13-15x^9-16x^5

Donald has x twenty-dollar bills and 11 ten-dollar bill. how much money does donald have? write your answer as an expression.

Indicate the formula for the following conditions: p^c(n,r)=

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”?