\(=x^3+ax^2+bcx+abc+\left(b+c\right)x^2+a\left(b+c\right)x\)
\(=x^2\left(x+a\right)+bc\left(x+a\right)+\left(b+c\right)x\left(x+a\right)\)
\(=\left(x+a\right)\left(x^2+bc+\left(b+c\right)x\right)\)
\(=\left(x+a\right)\left(x^2+bx+cx+bc\right)\)
\(=\left(x+a\right)\left[x\left(x+b\right)+c\left(x+b\right)\right]\)
\(=\left(x+a\right)\left(x+b\right)\left(x+c\right)\)