4 x minus 19 lesan 3 x minus 5 minus 2 less than or equal to 2 by 5 + X where X belongs to real number solve the inequation​

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”?