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One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

Simplify the expression. -2/5(10+15m-20n)

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”?