Decide whether each situation is best described by a linear, quadratic, or exponential function.
If the function is exponential: What is the growth factor. Is it doubling (factor of 2)? Tripling (factor of 3)? Factor of 5? 10?

High Fives

Two students started a club. At every meeting, students in attendance must high-five each of the other students. Club membership has been growing steadily by one student each meeting.

1 Is the function increasing or decreasing?

2 When the 2 students started the club (x=0), how many high-fives happened?

3 How many high-fives happen at the subsequent meetings…​

(3 students)
x=1
(4 students)
x=2
x=3 x=4

4 What is the form of this function? linear ☐ quadratic exponential☐

5 If it’s exponential,

Complete the function by filling in the coefficients:

𝑓(𝑥) = initial value 𝑎 growth factor 𝑏 x + horizontal asymptote 𝑘

Is it exponential growth? ☐ or decay? ☐

Going Viral

A student posted their animation of a puppy doing a back flip into a pile of laundry and the meme went viral! Every person that sees the meme falls in love with it and shares it with 10 new friends.

6 Is the function increasing or decreasing?

7 When the student posts it (x=0), how many total times has it been shared?

8 How many times will it have been shared after…​

(the next person shares)
x=1
(their friends share)
x=2
x=3 x =4

9 What is the form of this function? linear ☐ quadratic ☐ exponential

10 If it’s exponential,

Complete the function by filling in the coefficients:

𝑓(𝑥) = initial value 𝑎 growth factor 𝑏 x + horizontal asymptote 𝑘

Is it exponential growth? or decay? ☐

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