Write an exponential function from a table, graph or story

Answer Key - Grade 9 Math Worksheet

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

1. Read this first

   Growth table

   x	y
   0	3
   1	12
   2	48
   3	192

2. 1.

   Pia tracks a seed swap where each round brings in 4 times as many seeds. What function fits the table? Start with y =.

   y = 3(4)^x
3. 2.

   Ren counts sunflower seeds in a pattern game. What function fits the table? Start with y =.

   y = 7(3)^x
4. 3.

   Tala's art club tracks crayon drawings in a pattern game. What function fits the table? Start with y =.

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

   Zee stacks paper cups in a pattern game. What function fits the table? Start with y =.

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

   Ari's rocket-club graph shows a pattern. What function fits the graph? Start with y =.

   y = 2(4)^x
7. 6.

   Jun's graph shows another shrinking pattern. What function fits the graph? Start with y =.

   y = 162(1/3)^x

8. Growth table

   x	y
   1	6
   2	18
   3	54
   4	162

9. 7.

   Kira's bell-ringing game table starts at x = 1. What function fits the table? Start with y =.

   y = 2(3)^x
10. 8.

    Luz's bike-club table starts at x = 1. What function fits the table? Start with y =.

    y = 10(2)^x
11. 9.

    A science video starts with 50 bacteria, and the count doubles every 20 minutes. x is the number of 20-minute periods. What function gives Ren the count? Start with y =.

    y = 50(2)^x
12. 10.

    Zee folds a stack of 6 sheets in half again and again. Each fold doubles the layers. What function gives the layers after x folds? Start with y =.

    y = 6(2)^x