Can someone explain this step by step

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

Find the midpoint m of z1=(8+5i) and z2=(12+3i)

1.two more than the quotient of a number and 6 is equal to 7 use the c for the unknown number translate the sentence into an equation