1. The y-intercept of a line is on a graph where a line crosses through the y axis.
2. b is the y- intercept and m is the slope. For example something using y=mx+b could be written like y=3x+2 if the y-intercept is 2 and the slope is 3.
3. The slope is what describes the direction and steepness of a line on a graph. Rise and run mean that when you find a slope you must first find the rise over run. You must go from one dot on a graph to the next by first going up or down to where that you are on the same number on the y axis that the next point is, next go on the x axis and go left or right until you have reached the next point. For example if you went up 3 and over 2, the rise would be 3 and the run would be 2. The slope in that situation would be 3/2.
