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How do you factor #x^3-2x-21#?

Answer 1

Hazel Anglin

#(x^2+3x+7)(x-3)#

#x^3-2x-21 = x^3-3x^2+3x^2-9x+7x-21=x^2(x-3)+3x(x-3)+7(x-3)=(x^2+3x+7)(x-3)#[Ans]

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Answer 2

Abigail Allen

To factor the polynomial x^3 - 2x - 21, you can use a method like synthetic division or the rational root theorem to find its roots. Once you find a root, you can use polynomial long division or synthetic division to divide the polynomial by the root to obtain a quadratic factor. Then, you can factor the quadratic factor further if possible using methods like factoring by grouping or the quadratic formula.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.