\(=a^3-3a^2+7a^2-21a-\left(8a-24\right)\)hay
\(=a^2\left(a-3\right)+8a\left(a-3\right)-8\left(a-3\right)\)
\(=\left(a-3\right)\left(a^2+8a-8\right)\)
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\(a^3+4a^2-29a+24\)
\(=\left(a^3-3a^2\right)+\left(7a^2-21a\right)+\left(-8a+24\right)\)
\(=\left(a-3\right)\left(a^2+7a-8\right)\)
\(=\left(a-3\right)\left[\left(a^2-a\right)+\left(8a-8\right)\right]\)
\(=\left(a-3\right)\left(a-1\right)\left(a+8\right)\)
\(a^3+4a^2-29a+24\)
= \(a^3-a^2+5a^2-5a-24a+24\)
= \(a^2\left(a-1\right)+5a\left(a-1\right)-24\left(a-1\right)\)
= \(\left(a-1\right)\left(a^2-3a+8a-24\right)\)
= \(\left(a-1\right)\left(a-3\right)\left(a+8\right)\)
