helpp mee, cứu emm với mấy bồ ơiiii

`a)`

`(x+2)^3+(2-x)(4+2x+x^2)`

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

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

`=` `(x^3-x^3)+6x^2+12x+(8+8)`

`=` `6x^2+12x+16`

`b)`

`(x-1)^3+(x^2-3x+9)(x+3)+3x^2`

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

`=` `x^3-3x^2+3x-1+x^3+27+3x^2`

`=` `(x^3+x^3)+(-3x^2+3x^2)+3x+(-1+27)`

`=` `2x^3+3x+26`

`c)`

`(x+5)(x^2-5x+25)+6-x^3`

`=` `x^3+5^3+6-x^3`

`=` `x^3+125+6-x^3`

`=` `(x^3-x^3)+(125+6)`

`=` `131`

`d)`

`(3x+2)(9x^2-6x+4)-9x(3x^2+1)`

`=` `(3x)^3+2^3-9x.3x^2-9x.1`

`=` `27x^3+8-27x^3-9x`

`=` `(27x^3-27x^3)-9x+8`

 `=` `-9x+8`