\(=\left(x+2\right)^3+y^3\)
\(=\left(x+2+y\right)\left(x^2+4x+4-xy-2y+y^2\right)\)
\(x^3+y^3+6x^2+12x+8\)
=\(x^3+3.2.x^2+3.2^2.x+2^3+y^3\)
\(=\left(x+2\right)^3+y^3=\left(x+2+y\right)\left(\left(x+2\right)^2-\left(x+2\right)y+y^2\right)\)
\(=\left(x+y+2\right)\left(x^2+4x+4-xy-2y-y^2\right)\)