Discussion:
1) Vertical line = infinity (or no slope) "I say"
"Slope is always defined as rise/run. In a vertical line, you rise infinitely, but you have no run, so you have some number as your rise/0. Anything divided by 0 is undefined, so the slope of a vertical line is undefined."
2) a horizontal line equation would look something like: y= 0x + 5 (giving a 0 in the m position, so the slope is 0) So it becomes just y=5? Explain