How can you isolate the term ? f/2+9= 4 ? ? on both sides. The first ? has add, sub, multiple by, and divide by.
The second ? has -9, -4, 4,and 9.
​

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”?