Đáp án:
Giải thích các bước giải:
`x(y + z)^2 + y(x + z)^2 + z(x + y)^2 – 4xyz`
`= x(y^2 + 2yz + z^2) + y(x^2 + 2xz + z^2) + z(x + y)^2 – 4xyz`
`= xy^2 + 2xyz + xz^2 + x^2y + 2xyz + yz^2 + z(x + y)^2 – 4xyz`
`=(xy^2 + x^2y) + (xz^2 + yz^2) + z(x + y)^2`
`=xy(y + x) + z^2(x + y) + z(x + y)^2`
`=(x + y) [xy + z^2 + z(x + y)]`
`=(x + y) (xy + z^2 + zx + zy)`
`=(x + y) [(x(y +z) + z(y + z)]`
`=(x + y) (y + z) (x + z)`
