Pls answer 10 and 12 show your work

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827

M.xyz =radians. covert this radian measure to its equivalent measure in degrees.

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”?