Consider the graph of y = x^2 + 2 x - 1 . Graph by plotting the vertex and the y-intercept. Then graph the parabola by selecting the vertex FIRST and then the y-intercept.

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?

We just started the introduction into circles and i have no idea how to do this.

Which best explains why this triangle is or is not a right triangle ?