`#Sad`
`x^3-8(x+1) = -8x`
`⇔ x^3-8x-8 = -8x`
`⇔ x^3-8x-8+8x = 0`
`⇔ x^3-8 = 0`
`⇔ (x-2)(x^2-2x+4) = 0`
`⇔` \(\left[ \begin{array}{l}x-2=0\\x^2-2x+4=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=2\\x^2=-4+2x\end{array} \right.\)
`\text{Vì}` `x^2 >= 0`
`\text{Mà:}` `x^2 = -4+2x` `\text{(→loại)}`
`⇔ x-2 = 0`
`⇔ x = 2`
`\text{Vậy}` `x=2`
`\text{→Áp dụng:}` `A^3+B^3 = (A+B)(A^2-AB+B^2)`
