Write an exponential function from a table, graph or story

Answer Key - Grade 9 Math Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. Read this first

   Growth table

   x	y
   0	3
   2	12
   4	48

2. 1.

   Ari measures a plant pattern only on even days. The values are exponential, but the inputs skip. What function fits the table? Start with y =.

   y = 3(2)^x
3. 2.

   Bo records a star pattern every other round. The values are exponential, but the inputs skip. What function fits the table? Start with y =.

   y = 5(3)^x
4. 3.

   Esme checks a jar puzzle every second step. The values are exponential, but the inputs skip. What function fits the table? Start with y =.

   y = 10(2)^x
5. 4.

   Kira knows f is exponential, with f(1) = 12 and f(3) = 108. Every value is positive. What is f? Start with y =.

   y = 4(3)^x
6. 5.

   Luz knows f is exponential, with f(1) = 10 and f(3) = 40. Every value is positive. What is f? Start with y =.

   y = 5(2)^x
7. 6.

   Noah knows f is exponential, with f(1) = 24 and f(3) = 384. Every value is positive. What is f? Start with y =.

   y = 6(4)^x
8. 7.

   Pia drops a play ball from 120 cm. Each bounce reaches 1/2 of the height before it. What function gives the height after x bounces? Start with y =.

   y = 120(1/2)^x
9. 8.

   A school chess tournament starts with 64 players, and half are left after each round. What function gives the players Ren sees left after x rounds? Start with y =.

   y = 64(1/2)^x
10. 9.

    Tala shines light through filters. Each filter lets through 1/4 of the light that reaches it. After 1 filter, 200 units are left. What function gives the light after x filters? Start with y =.

    y = 800(1/4)^x
11. 10.

    Zee's bouncy ball reaches 90 cm on bounce 1, and each bounce is 1/2 as high as the one before. What function gives the height after x bounces? Start with y =.

    y = 180(1/2)^x