Разложите на множители 1)2u^3-2v^3 2)3z^3+3w^3 3)nx^3+nz^3 4)w^4-w 5)z^4+8z 6)x^4-16z^4 7)81-k^4

1) 2( u^3 - v^3) = 2( u - v)(u^2 + uv + v^2)
2) 3( z^3 + w^3) = 3( z + w)(z^2 - zw + w^2)
3) n( x^3 + z^3) = n( x+ z)(x^2 - xz + z^2)
4) w( w^3 - 1) = w( w - 1)(w^2 + w + 1)
5) z( z^3 +8) = z( z + 2)(z^2 - 2z + 4)
6) ( x^2 - 4z^2)(x^2 + 4z^2)
7) ( 9 - k^2)(9 + k^2)