12) Why are the numbers 9 and 0, when combined, not considered a zero pair?

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?

Which expression converts 45 degree to radians

How many solutions does the nonlinear system of equations graphed below have?