Use the linear combination method to solve this system of equations. What is the value of x? 3 x + 7 y = 31. Minus 3 x minus 2 y = negative 1 Negative 6 Negative 3 and two-thirds 3 and two-thirds 6

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”?