Hello pleaseee help me! Will really appreciate it

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?

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

What is the solution to the system of equation graphed belowa.(0,-4)b.(2,5),1),-3)