Slope Help:
Video: Calculating the Slope of a line between two points. (Patrick JMT)
Finding the slope between two points requires you to
find how much y-changes and divide it by how much x-changes. It is often thought of as 
. For example,
to find the slope between
(-4, 6) and (5, -10), we first determine that the y-value
changes by -16. We then see that the
x-value changes by +9, so our slope must be 
.
Rate of change is the same idea as slope, you may need to read some context to the problem, then explain what it means. For example…
A red sea urchin grows its entire life, which can last 200 years. If at age 30 the sea urchin has a diameter of 11.9 cm and at age 110 it has a diameter of 15.5 cm, what is the average growth rate of this urchin over the given period and what does this mean?
The diameter changes 3.6 cm and the number of years
is 80, so the slope is 
cm/yr or .045 cm/yr, which means that over the period
of 80 years the sea urchin averages .045 centimeters of growth every year.