giải cho mik với Help me

Đáp án+Giải thích các bước giải:

`a)`

`A=(3x+7)(2x+3)-(3x-5)(2x+11)`

`=6x^2+9x+14x+21-(6x^2+33x-10x-55)`

`=6x^2+9x+14x+21-6x^2-33x+10x+55`

`=(6x^2-6x^2)+(9x+14x-33x+10x)+(21+55)`

`=76`

`b)`

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

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

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

`=2`

`c)`

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

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

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

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

`=-2`

`d)`

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

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

`=8x^3+27-8x^3+2`

`=(8x^3-8x^3)+(27+2)`

`=29`

`e)`

`(4x-1)^3-(4x-3)(16x^2+3)`

`=(4x)^3-3.(4x)^2 .1+3.4x.1^2-1^3-(64x^3+12x-48x^2-9)`

`=64x^3-48x^2+12x-1-64x^3-12x+48x^2+9`

`=(64x^3-64x^3)+(-48x^2+48x^2)+(12x-12x)+(-1+9)`

`=8`

`#ld`