`***`$\color{#1c1c1c}{\text{t}}$$\color{#363636}{\text{r}}$$\color{#4f4f4f}{\text{u}}$$\color{#696969}{\text{m}}$$\color{#828282}{\text{t}}$$\color{#9c9c9c}{\text{td}}$

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

`=x^3+8-x+1-x^2-x-1`

`=x^3-x^2-x-x+8+1-1`

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

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`(2a - 3b)^2 + (2a - b)(4a^2 + 2ab + b^2) - (a - b)^3`

`=4a^2-12ab+9b^2+8a^3-b^3-a^3+3a^2b-3ab^2+b^3`

`=8a^3-a^3+4a^2-12ab-b^3+b^3+9b^2+3a^2b-3ab^2`

`=7a^3+4a^2-12ab+9b^2+3a^2b-3ab^2`