Giúp mik làm bài thu gọn bthuc có thể lm theo Hằng Đẳng Thức

Đáp án+Giải thích các bước giải:

a,

`(2x-5)(x+1)-(x-3)^3`

`=(2x^2-5x+2x-5)-(x^3-9x^2+27x-27)`

`=2x^2-3x-5-x^3+9x^2-27x+27`

`=-x^3+(9x^2+2x^2)-(27x+3x)+(27-5)`

`=-x^3+11x^2-30x+22`

b,

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

`=(9x^2-6x+1)-9(x^2-1)`

`=9x^2-6x+1-9x^2+9`

`=(9x^2-9x^2)-6x+1+9`

`=-6x+10`

c,

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

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

`=1-x^3-x^3-8`

`=-7-2x^3`

d,

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

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

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

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

`=3x^2+3x`

e,

`(4x-1)(4x+1)-(2x+3)^3+8x^3+20x^2`

`=(16x^2-1)-(8x^3+36x^2+54x+27)+8x^3+20x^2`

`=16x^2-1-8x^3-36x^2-54x-27+8x^3+20x^2`

`=(-8x^3+8x^3)+(16x^2+20x^2-36x^2)-54x-(1+27)`

`=-54x-28`