Ch5

1. This video explains partial and direct variation and also goes into teaching what slope is.

2. This video introduces direct and partial variation, 2 simple and important terms you need to understand.

3. Introduction to slope. This video explains what slope is and why and how it can be used. Slope is a ratio, and a rate of change. If the slope is high, then the rate of change is high.

4. This Math Antics video explains the equation of a line, and the meaning of m (slope) and b (y-intercept).

5. This Khan Academy video explains how slope is a rate of change.

6. This video explains partial and direct variation, along with first differences. (be careful around 2:05, a dog starts barking and it is very loud)

7. This video explains what first differences are, how to calculate them, and how they indicate if a relationship is linear or non-linear.

8. This video also explains what first differences are and how that can be applied to determine partial or direct variation, or if the relationship is learn or non-linear.

9. This video shows first differences, and also shows an example of a relationship that is NOT linear and what that looks like. In case you are curious, the kind of relationship that it shows is related to x(squared), and this type of relationship is called a quadratic.