Đáp án+Giải thích các bước giải:

`color{#ffd0d0}{l}color{#ffdada}{y}color{#ffebd6}{n}color{#fff7e1}{l}color{#e6ffdd}{y}color{#d6f9ff}{n}color{#f0eaff}{n}`

`a,`

`x^2-y^2-2x-2y`

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

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

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

`b,`

`3x^2-3y^2-2(x-y)^2`

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

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

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

`=(x-y)(x+5y)`

`c,`

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

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

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

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

`d,`

`x^2-2x-4y^2-4y`

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

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

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

`e,`

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

`=x^2(x-4)-9(x-4)+36`

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

`=(x-4)(x-3)(x+3)`

`f,`

`x^3+2x^2+2x+1`

`=x^3+x^2+x^2+x+x+1`

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

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