On complex numbers
1) what is the reciprocal of 6i
2) what is the additive inverse of -4+5i
3) find the multiplicative inverse of 2+i
4) find the reciprocal of -3+5i
5) find the magnitude of 5-12i

Which of the following expressions are equivalent ?

The lengths of nails produced in a factory are normally distributed with a mean of 4.91 centimeters and a standard deviation of 0.05 centimeters. find the two lengths that separate the top 4% and the bottom 4%. these lengths could serve as limits used to identify which nails should be rejected. round your answer to the nearest hundredth, if necessary.

If you have 12 feet of string and you cut it into equal length of 5 inches each how much string will be left