What is y-13=-20 i dont know the answers and it's kinda hard to me and i need some

Assemble the proof by dragging tiles to the statements and reasons column

5(-9w) put expression in distributive property

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”?