Final answer:
The other factor of the equation x⁴+x²-20, given one factor is x²+5, is x²-4.
Step-by-step explanation:
In the given equation x⁴+x²-20, we already know that one factor of it is x²+5. We find the other factor by dividing the original equation by the known factor. If we draw out the long division, we find that x²-4 is the quotient, which means it is the other factor of the original equation. Therefore, the correct answer to your question is (a) x²-4.
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