Extra Set

Grade 8 · Unit 4 · MIA · Version A · F6A7

Mixed set · Unit 4

Name ________________

Date ________________

Period ________________

1.
The mapping { (2, 1), (2, 7), (3, 8) } — is it a function?
Answer. no
Input 2 is paired with two outputs.
2.
A function is f(x) = 3x + 10. Find f(6).
Answer. 28
f(6) = 3(6) + 10 = 28.
3.
f(x) = 2x and g(x) = 6x. Which function has the greater rate of change?
Answer. g
Rate of change is the slope: 6 > 2.
4.
A car travels at a steady speed, then brakes to a stop. Speed vs. time?
Answer. A horizontal segment, then a decreasing segment to 0.
A horizontal segment, then a decreasing segment to 0.
5.
The mapping { (2, 1), (2, 7), (3, 8) } — is it a function? Write a complete answer — Theo will compare with a partner.
Answer. no
Input 2 is paired with two outputs.
6.
A function is f(x) = 2x + 9. Find f(6). Then Nora needs 5 of that amount. What is the total they need?
Answer. 105
f(6) = 2(6) + 9 = 21. Then multiply by 5: 105.
7.
f(x) = 2x and g(x) = 4x. Which function has the greater rate of change? Write a complete answer — Ava will compare with a partner.
Answer. g
Rate of change is the slope: 4 > 2.
8.
A car travels at a steady speed, then brakes to a stop. Speed vs. time? Then Sam needs 2 of that amount. What is the total they need?
Answer. A horizontal segment, then a decreasing segment to 0.
A horizontal segment, then a decreasing segment to 0. Then multiply by 2: A horizontal segment, then a decreasing segment to 0..
9.
The mapping { (1, 4), (2, 4), (3, 5) } — is it a function? Write a complete answer — Luis will compare with a partner.
Answer. yes
Each input appears once.
10.
A function is f(x) = 4x + 4. Find f(4). Then Theo needs 5 of that amount. What is the total they need?
Answer. 100
f(4) = 4(4) + 4 = 20. Then multiply by 5: 100.
11.
Think
Grace tried this problem:
f(x) = 2x and g(x) = 4x. Which function has the greater rate of change?
Grace wrote g (check this). That is not correct. What is the right answer?
Answer. g
Grace’s answer g (check this) is off. Rate of change is the slope: 4 > 2.
12.
Think
Sam tried this problem:
A car travels at a steady speed, then brakes to a stop. Speed vs. time?
Sam wrote A horizontal segment, then a decreasing segment to 1.. That is not correct. What is the right answer?
Answer. A horizontal segment, then a decreasing segment to 0.
Sam’s answer A horizontal segment, then a decreasing segment to 1. is off. A horizontal segment, then a decreasing segment to 0.

Original extra practice. Keys are computed from the items, not guessed.

MIA · Mixed set · Unit 4