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Đáp án`+`Giải thích các bước giải:

 `1, x^2 - 16y^2`

`= x^2 - (4y)^2`

`= (x - 4y)(x + 4y)`

`2, 9a^2 - 6ab + b^2`

`= (3a)^2 - 2.3a.b + b^2`

`= (3a - b)^2`

`3, 25x^2 + 10x + 1`

`= (5x)^2 + 2.5x.1 + 1^2`

`= (5x + 1)`

`4, (x + y)^2 - 4`

`= (x +y)^2 -2 ^2`

`= (x + y + 2)(x +y -2)`

`5, 8x^3 + 27y^3`

`= (2x)^3 + (3y)^3`

`= (2x + 3y)(4x^2 - 6xy + 9y^2)`

`6, x^3 - 6x^2 + 12x - 8`

`=x^3 - 3.x^2 . 2 + 3.x . 2^2 - 2^3`

`= (x - 2)^3`

`7, (x - 1)^3 +1 25`

`= (x - 1)^3 + 5^3`

`= (x - 1 + 5)[(x - 1)^2 - (x - 1)5 + 5^2]`

`= (x + 4)(x^2 - 2x + 1 - 5x + 5 + 25)`

`= (x + 4)(x^2 - 7x + 31)`

`8, x^4 - y^4`

`= (x^2 - y^2)(x^2 + y^2)`

`= (x -y)(x +y)(x^2 +y^2)`

`***`sharksosad