Function notation: read and evaluate f(x), including f(x + 2) and f(2x)

Answer Key - Grade 9 Math Worksheet - Building Confidence

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

1. Read this first

   Use the table

   input m: minutes	output f(m): liters
   1	12
   3	20
   5	28
   7	36

2. 1.

   Bo fills a tub, and the water splashes everywhere. The table shows f(m), the liters in the tub after m minutes. What is f(3)?

   20
3. 2.

   Esme runs a lemonade stand with a very loud sign. The table shows f(c), the dollars in the cash jar after c cups sold. What is f(3)?

   13
4. 3.

   Jun bikes away from the start flag on a bumpy path. The table shows f(h), the distance in km after h hours. What is f(4)?

   16
5. 4.

   Kira's sunflower stretches toward the sun. The table shows f(w), its height in cm after w weeks. For which w is f(w) = 14?

   6
6. 5.

   Luz bakes cookies, and the rack fills up. The table shows f(t), the cookies on the rack after t minutes. For which t is f(t) = 44?

   12
7. 6.

   Milo counts riders on a crowded bus. The table shows f(m), the riders on board after m minutes. For which m is f(m) = 19?

   15
8. 7.

   Noah folds paper cranes (one is very wobbly). The table shows f(m), the cranes made after m minutes. For which m is f(m) = 25?

   12
9. 8.

   Ren runs a snack cart. The price is f(n) = 5n + 1 dollars for n snacks. Ren writes f(6) = 5 × 6 + 1. What is f(6)?

   31
10. 9.

    Tala camps at a lake. A campsite costs f(d) = 2d + 7 dollars for d nights. Tala writes f(3) = 2 × 3 + 7. What is f(3)?

    13
11. 10.

    Zee orders balloons for a party. The cost is f(b) = 4b + 6 dollars for b balloons. Zee writes f(5) = 4 × 5 + 6. What is f(5)?

    26