Write problem in standard form a+bi
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Find the nonpermissible replacement for binthis expression.b2/5b +5

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

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”?