Question

凱蒂

(x²+2x+4)(x²+2x-6)+21
因式分解

Answer 1

Choosen As Best Answer

算術平均數

設y=x²+2x
(y+4)(y-6)+21
=y²-2y-24+21
=y²-2y-3
=(y-3)(y+1)
代回 y=x²+2x
=(x²+2x-3)(x²+2x+1)

凱蒂

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