64, –48, 36, –27, which formula can be used to describe the sequence? f(x + 1) = f(x) f(x + 1) = f(x) f(x) = f(x + 1) f(x) = f(x + 1)

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”?