How do you do this question? and what does the bar lines mean, is it absolute value?

Karianne and lucius are analyzing a linear function on a graph. karianne says that unit rate is equal to rate of change, but that slope is calculated differently. lucius says that unit rate, rate of change, and slope are calculated the same way. who is correct? explain your answer.

Which of the following is the missing term, a2, of the geometric sequence in which a1=2 and a3=200

Find the cosine function that is represented in the graph.