Directions: for questions 15 through 20, expand each expression. directions: for questions 21 through 24, factor each expression to its simplest form. 25 through 26 choose letter matching answer

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”?