Can you please help me ​

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 are the solutions of the system? solve by graphing. y = -x^2 - 3x + 2 y = -2x + 2

Solve the triangle. a = 21°, c = 105°, c = 5