Describe the rate of change modeled by this graph.
a) positive
b) negative
c) no change
d) a change that is undefined

Hello!  Finding the rate of change used to really confuse me, but after learning about it a little more I understand it so much better.  To find whether a slope line is either negative or positive, you find the lowest point graphed on the line. So, for this example, it would be the point that intercepted the X axis at -8.  Then, just follow the line.  IF the line leads to a positive quadrant, then the line is positive.  IF the line leads to a negative quarderent, then the line is negative.  IF the line is a straight line, then it is no change, and if the line is a vertical line with no change it is a change that is undefined.  

I hoped this helped in some way, and if you have any further questions feel free to shoot me a message or another question.  Good luck :)

Constant: When the graph has a straight line, because the constant of proportionality wouldn't change. 
Decreasing: Going from up to down, or otherwise known as a negative correlation. 
Increasing: Going from down to up. Values increase. 

Since this line is increasing, the answer would be positive. 

If you need an equation, it would be y=2x+8, y would be how long it grew, x being weeks.if you need how long he was asleep, it would be 4 weeks if he started with no beard, the equation would be x=8÷2if he did have a beard before hand, the equation would be 2w+x=8