4x + 19 = ___+ 12 Choose a value to fill in the blank that would make this equation have no solutions.
Pls help

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”?