Answer:
{(1, 2), (2, 3), (3, 4), (4, 5)}
Explanation:
Given:
Which relation is a function?
{(1, 2), (2, 3), (3, 4), (4, 5)}
{(1, 2), (2, 1), (1, 3), (3, 1)}
{(0, 2), (0, 4), (0, 6), (0, 8)}
{(1, 2), (3, 4), (5, 6), (1, 8)}
Solve:
To know which relation is a function, we must know how it a function.
There are two ways to figure out.
One way is by looking at a graph - Vertical Line Test : Draw a vertical line and if the line hits the graph one time, the graph is a function.
Another way is by looking at the function : In a function there can be only one x- value(Input) for every y- value(Output). Meaning that there can be duplicate y-value but can't have any in x - value. If there is duplicate x-value meaning it not a function.
Thus, now let's look at each answer choice.
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Starting with : {(1, 2), (2, 3), (3, 4), (4, 5)}
Input (x) | Output (y)
1 2
2 3
3 4
4 5
There is only one x- value. Therefore, it a function.
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Next : {(1, 2), (2, 1), (1, 3), (3, 1)}
Input (x) | Output (y)
1 2
2 1
1 3
3 1
There are two 1's in x-value(Input). Therefore, it isn't a function
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Then: {(0, 2), (0, 4), (0, 6), (0, 8)}
Input (x) | Output (y)
0 2
0 4
0 6
0 8
All of the x-value(Input) are the same. Therefore, it isn't a function
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Lastly: {(1, 2), (3, 4), (5, 6), (1, 8)}
Input (x) | Output (y)
1 2
3 4
5 6
1 8
There are two 1's in x-value(Input). Therefore, it isn't a function
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