Can someone me with my homework with these two questions !

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?

What expression is equivalent to 42x-56y

Ihave trouble finding the nth term of a linear sequence