Write a 6th degree binomial in four variables

What is the product of the radical expression. (7-2square root) (8+2 square root)

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?

True or false look at the picture pls : /