22: \(=\left(a+b\right)^3+c^3-3ab\left(a+b\right)-3abc\)
\(=\left(a+b+c\right)\left(a^2+2ab+b^2-ac-bc+c^2\right)-3ab\left(a+b+c\right)\)
\(=\left(a+c+b\right)\left(a^2+b^2+c^2-ab-ac-bc\right)\)
23: \(=\left(a+b+c-a\right)\left[\left(a+b+c\right)^2+a\left(a+b+c\right)+a^2\right]-\left(b+c\right)\left(b^2-bc+c^2\right)\)
\(=\left(b+c\right)\left(3a^2+b^2+c^2+3ab+2bc+3ac-b^2+bc-c^2\right)\)
\(=\left(b+c\right)\left(3a^2+3ab+3bc+3ac\right)\)
\(=3\left(a+c\right)\left(b+c\right)\left(a+b\right)\)
24: \(=x^3-2x^2+x^2-4\)
\(=x^2\left(x-2\right)+\left(x+2\right)\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2+x+2\right)\)
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