The equation for the given relation is a quadratic equation:

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How to write an equation for the given relation?</h3>
Here we have the relation:
D = {(x, y); (3, 9), (5, 25), (-2, 4), ...}
Notice that for each coordinate point, we can see that the output is equal to the square of the input:

Then the equation is just:

If you want to learn more about quadratic equations:
brainly.com/question/1214333
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