Worked examples
Two examples
Example 1
Which rule matches every row?
| x | 0 | 1 | 2 | 3 |
|---|---|---|---|---|
| y | 1 | 3 | 5 | 7 |
- Try y = 2x + 1: 0 gives 1, 1 gives 3, 2 gives 5, 3 gives 7.
- Every row matches.
Answer: y = 2x + 1
Example 2
Which rule matches every row?
| x | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| y | 2 | 5 | 10 | 17 |
- The changes are 3, 5, 7: not the same, so not a straight line.
- Try y = x2 + 1: 1 gives 2, 2 gives 5, 3 gives 10, 4 gives 17.
Answer: y = x2 + 1
Where this is taught: Quiz 41: Functions, “Matching a table to its rule: check every row”
The drill
Ten problems
How many:
Tap your answer to each one, then press Check my answers at the bottom.Circle your answer to each one. The answer key, with the reasoning, is on the last page.