Phân tích các đa thức thành nhân tử

`h, 4x^2 - y^2 - 4y - 4`

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

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

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

`i, x^3 - 3x^2 - 3x + 1`

`= (x + 1)(x^2 - x + 1) - 3x(x + 1)`

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

`j, x^3 + 9x^2 - 4x - 36``

`= x^2 (x + 9) - 4(x + 9)`

`= (x + 9)(x^2 - 4)`

`= (x + 9)(x - 2)(x + 2)`

`k, x^6 - x^4 + 2x^3 + 2x^2`

`= x^6 - 2x^4 + x^2 + x^4 + 2x^3 + x^2`

`= (x^3 - x)^2 + (x^2  + x)^2`

`= x^2 (x - 1)^2 (x + 1)^2 + x^2 (x + 1)^2`

`= x^2 (x + 1)^2 (x^2 - 2x + 1 + 1)`

`= x^2 (x + 1)^2 (x - 2x + 2)`

`l, 4x^2 -16xy - 9y^2`

`= 4x^2 + 2xy - 18xy - 9y^2`

`= 2x(2x + y) - 9y(2x + y)`

`= (2x + y)(2x - 9y)`

`m, x^4 + 64`

`= x^4 + 16x^2 + 64 - 16x^2`

`= (x^2 + 8)^2 - (4x)^2`

`= (x^2 + 8 - 4x)(x^2 + 4x + 8)`

`n, x^2 - y^2 + 2x + 1`

`= (x + 1)^2 - y^2`

`= (x + 1 - y)(x + 1 + y)`