The SLOPE of a line is a number that tells us how steep the line is.
To interact with applet, move the 2 BLUE POINTS anywhere on the screen you'd like. As you do, take note of the displayed slope.
See if you can figure out how the slope of a line is calculated just by looking at it.
After interacting with this applet for a few minutes, take another few minutes to carefully answer the questions that follow.

Questions:
1) There are four types of slope: Positive, Negative, Zero, and Undefined.
What causes a line to have POSITIVE slope? Explain as best as you can.
What causes a line to have NEGATIVE slope? Explain as best as you can.
What causes a line to have ZERO slope? Explain as best as you can.
What causes the slope of a line to be UNDEFINED? Explain as best as you can.