Which numbers can you multiply the equations by to form opposite terms for the x-variable? Multiply –3x + 2y = 20 by _ . Multiply 2x + 11y = –1 by _ .

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”?