Question

The following graph shows the quantity of pencil sales (s) with respect to the day in August (d) in various office supply stores. Which of the following is most likely to be the equation of the trend line?

d= - 20/3s - 20
d = 20/3s - 20
s = -20/3d - 20
s= 20/3d - 20

https://static.k12.com/eli/bb/1211/4_68960/2_33592_16_68976/a96bf17c229e063e24091eb1b909924af9c7c7b4/media/80038125d95831be7597a5f6b289b93a4e2c1562/mediaasset_952313_1.jpg

Answer 1

in a "normal" graph, the horizontal axis is x and the vertical is y
in your graph, what do "d" and "s" correspond to ?

Answer 2

in other words, which of s or d is the "y" ?

Answer 3

s is y

Answer 4

ok. the equation of a line in point slope form is
y= mx + b

so in this case, I would expect to see
s= m d + b
where m is the slope and b is the y-intercept

knowing that, you can cross of two of the choices.

Answer 5

any idea how to decide which of the two remaining choices is the correct answer ?

I would use the idea that a line that slopes up and to the right has positive slope

Answer 6

would it be d?

Answer 7

what is the slope in choice D ?

Answer 8

20/3

Answer 9

yes, and that is positive. that means that line slopes up and to the right
which is what we want.
(the other choice slopes down)

Answer 10

so d is correct right?

Answer 11

yes, D is correct. it has the correct form s= m d + b
and it has the correct slope (positive)

Answer 12

ty