Worked examples
Two examples
Example 1
Is this set of pairs a function? (1, 4), (2, 5), (3, 4), (5, 9)
- No x-value appears twice, so each input has one output.
- The same y twice (4) is allowed.
Answer: Yes
Example 2
Is this set of pairs a function? (2, 3), (4, 1), (2, 7), (6, 0)
- x = 2 appears twice, with two different outputs, 3 and 7.
Answer: No
Where this is taught: Quiz 41: Functions, “Checking a table or a list of pairs”
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.