Đáp án:
Giải thích các bước giải:
`1, 2xy + 3z + 6y + xz`
`= (2xy + 6y) + (3z + xz)`
`= 2y(x + 3) + z(3 + x)`
`= (x + 3)(2y + z)`
`2, 16x^2 - (x + 1)^2`
`= (4x)^2 - (x + 1)^2`
`= [4x - (x + 1)][4x + (x + 1)]`
`= (4x - x - 1)(4x + x + 1)`
`= (3x - 1)(5x + 1)`
`3, x^2 - 6x - 7`
`= x^2 + x - 7x - 7`
`= x(x + 1) - 7(x + 1)`
`= (x + 1)(x - 7)`
`4, 3x^2 + 6xy + 3y^2 - 12z^2`
`= 3(x^2 + 2xy + y^2 - 4z^2)`
`= 3[(x + y)^2 - (2z)^2]`
`=3(x + y + 2z)(x +y - 2z)`
`5, 4x^3 + 4x^2 y + xy^2 - 25x`
`= x(4x^2 + 4xy + y^2 - 25)`
`= x[(2x)^2 + 2.2x.y + y^2 - 25]`
`= x[(2x + y)^2 - 5^2]`
`= x(2x + y + 5)(2x + y - 5)`
