Find all the rational roots of $2x^4 - x^3 - 18x^2 + 14x + 15 = 0.$  Enter all the rational roots, separated by commas.
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<|im_start|>user
Find all the rational roots of $2x^4 - x^3 - 18x^2 + 14x + 15 = 0.$  Enter all the rational roots, separated by commas.
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user
\frac{5}{2},-3
Find all the rational roots of $2x^4 - x^3 - 18x^2 + 14x + 15 = 0.$  Enter all the rational roots, separated by commas.
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