What can you do to the equation 1/x - 1/3 = 1/6 to make it easier to solve?

Write a corresponding real world problem to represent 2x - 125=400

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”?

[tex]5 \times1 \frac{12}{13} [/tex] me