Grade 8 · Math · Unit 6 of 13

Tables, Graphs & Linear Relations

Find missing values in y = mx + b

What your child practises

Using an equation like y = 3x + 2 to build a table of values, find a missing x or y, and describe how the variables change together.

Alberta Curriculum learning outcome: PR1 · ordered pairs, tables of values and graphs of linear relations with whole-number data

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

Question 1
In the relation y = 3x − 4, by how much does y change each time x increases by 1?
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3
Hint: The number multiplying x is 3, so y changes by 3 for each step of 1 in x.
Question 2
Which ordered pair is on the graph of y = 5x + 3?
- (4, 24)
- (4, 20)
- (4, 22)
- (4, 23)
Show answer
(4, 23)
Hint: Substitute x = 4: 5 × 4 + 3 = 23.
Question 3
The ordered pair (?, 24) is on the line y = 4x + 4. What is the missing x-value?
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5
Hint: Put y = 24 in the equation: 24 = 4x + 4. Undo the addition, then divide by 4: x = 5.
Question 4
For the relation y = 4x + 3, what is y when x = 7?
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31
Hint: Replace x with 7: 4 × 7 + 3 = 31.
Question 5
The table shows a linear relation. What number goes in place of the ?
Table of values
x y
0 -1
1 2
2 ?
3 8
4 11
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5
Hint: Look at how y changes each time x goes up by 1. It changes by 3, so y = 5 when x = 2.
Question 6
Which equation matches the table of values?
x y
1 9
2 12
3 15
4 18
- y = 6x + 3
- y = 3x − 6
- y = 3x + 6
- y = 4x + 6
Show answer
y = 3x + 6
Hint: Test the first row: x = 1 gives y = 9. Only y = 3x + 6 works for every row.