Simplify (x+y+z)^3

${(x + y + z)}^{3}$

Use the Multinomial Theorem.

$x^{3} + 3 x^{2} y + 3 x y^{2} + y^{3} + 3 x^{2} z + 6 x y z + 3 y^{2} z + 3 x z^{2} + 3 y z^{2} + z^{3}$

Reorder.

Move $3 y^{2} z$ .

$x^{3} + 3 x^{2} y + 3 x y^{2} + y^{3} + 3 x^{2} z + 6 x y z + 3 x z^{2} + 3 y^{2} z + 3 y z^{2} + z^{3}$

Move $y^{3}$ .

$x^{3} + 3 x^{2} y + 3 x y^{2} + 3 x^{2} z + 6 x y z + 3 x z^{2} + y^{3} + 3 y^{2} z + 3 y z^{2} + z^{3}$

Move $3 x y^{2}$ .

$x^{3} + 3 x^{2} y + 3 x^{2} z + 3 x y^{2} + 6 x y z + 3 x z^{2} + y^{3} + 3 y^{2} z + 3 y z^{2} + z^{3}$