If the slope of a line is m = -7, find the slope of the lines that are parallel and perpendicular to the line.

2-digit numbers less than 91 which are 1 less than a multiple of 10

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?

For what values of x is x2 + 2x = 24 true?