Correct product for (6 - d)(d 2 - 5 + 3d) 6d2 - 30d

What would the rule be for the reflection of y=-3

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”?

Can someone me find the original price? the discount is 5% and the sale price is $68.40