What has two sides but can sometimes look like a line

Solve |x| > -9 a) {x|x< -9 or x> 9} b) all reals c) no solution

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 inequality statement describes the two numbers on a number line? "? 7 and a number 5 units to the right of ? 7"