You described perfectly what to do. Now, nothing is stopping you. JUST DO IT. Pick ANY four values for x that you want. Use each of them to evaluate y. You are FREE to pick any four values for x.
Set up a table for x and y values.
x | y
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* |
* |
* |
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Try to pick some values which will be convenient for evaluating y. Choose 0, -3, 3, -6, 6. Those are only SOME suggestions. Can you see why?