Đáp án + Giải thích các bước giải:
`e` `(x+8)(x-8)-x^2`
`=x^2-8^2-x^2`
`=x^2-64-x^2`
`=-64`
`g)` `(x+2)^3+x(1-x^2)`
`=x^3+3*x^2*2+3*x*2^2+2^3+x(1-x^2)`
`=x^3+6x^2+12x+8+x-x^3`
`=6x^2+13x+8`
`h)` `(x+1/3)^3+(1-x)^3`
`=(x+1/3+1-x)[(x+1/3)^2-(x+1/3)(1-x)+(1-x)^2]`
`=4/3[x^2+2*x*1/3+(1/3)^2-(x-x^2+1/3-1/3x)+(1-2x+x^2)]`
`=4/3(x^2+2/3x+1/9-x+x^2-1/3+1/3x+1-2x+x^2)`
`=4/3[(x^2+x^2+x^2)+(2/3x-x+1/3x-2x)+(1/9-1/3+1)]`
`=4/3(3x^2-2x+7/9)`
`=4x^2-8/3x+28/27`
`i)` `(4x-1)(16x^2+4x+1)-x(4x^2-1)`
`=(4x-1)[(4x)^2+4x*1+1^2]-4x^3+x`
`=(4x)^3-1^3-4x^3+x`
`=64x^3-1-4x^3+x`
`=60x^3+x-1`.
