My handwriting is Pretty bad

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”?

Question 10 of 211 pointuse the elimination method to solve the system of equations. choose thecorrect ordered pair.10x +2y = 643x - 4y = -36a. (4,12)b. (-3, 11)c. (2,10)d. (-5, 8)

How are algebraic expressions evaluated using substitution?