Help me plsss i need for today

Sam claims that cos x =sin y if x and y are congruent angels. is sam correct ?

Write the following as a base and exponent

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”?