Đáp án + Giải thích các bước giải:
`(x-y+z)^3`
`=(x-y+z)(x-y+z)(x-y+z)`
`=[x(x-y+z)-y(x-y+z)+z(x-y+z)](x-y+z)`
`=(x^2-xy+xz-xy+y^2-yz+xz-yz+z^2)(x-y+z)`
`=(x^2+y^2+z^2-2xy+2xz-2yz)(x-y+z)`
`=x(x^2+y^2+z^2-2xy+2xz-2yz)-y(x^2+y^2+z^2-2xy+2xz-2yz)+z(x^2+y^2+z^2-2xy+2xz-2yz)`
`=x^3+xy^2+xz^2-2x^2y+2x^2z-2xyz-x^2y-y^3-yz^2+2xy^2-2xyz+2y^2z+x^2z+y^2z+z^3-2xyz+2xz^2-2yz^2`
`=x^3-y^3+z^3+3xy^2+3xz^2-3x^2y+3x^2z-6xyz-3yz^2+3y^2z`
