`a)(x+2)³-x(x+3)²=2`
`⇔x³+6x²+12x+8-x(x²+6x+9)=2`
`⇔x³+6x²+12x+8-x³-6x²-9x=2`
`⇔(x³-x³)+(6x²-6x²)+(12x-9x)+8=2`
`⇔3x+8=2`
`⇔3x=2-8`
`⇔3x=-6`
`⇔x=(-6):3`
`⇔x=-2`
Vậy `x=-2`
`b)(1-x)³+(x-2)(x²+2x+4)-3x(x+2)=11`
`⇔1-3x+3x²-x³+x³-8-3x²-6x=11`
`⇔(-x³+x³)+(3x²-3x²)+(-3x-6x)+(1-8)=11`
`⇔-9x-7=11`
`⇔-9x=11+7`
`⇔-9x=18`
`⇔x=18:(-9)`
`⇔x=-2`
Vậy `x=-2`
`c)(x-2)(x²+2x+4)-x(x²-3)=7`
`⇔x³-8-x³+3x=7`
`⇔(x³-x³)+3x-8=7`
`⇔3x-8=7`
`⇔3x=7+8`
`⇔3x=15`
`⇔x=15:3`
`⇔x=5`
Vậy `x=5`
`d)x(x+1)²-(x-1)³-5x(x+2)=9`
`⇔x(x²+2x+1)-(x³-3x²+3x-1)-5x²-10x=9`
`⇔x³+2x²+x-x³+3x²-3x+1-5x²-10x=9`
`⇔(x³-x³)+(2x²+3x²-5x²)+(x-3x-10x)+1=9`
`⇔-12x+1=9`
`⇔-12x=9-1`
`⇔-12x=8`
`⇔x=-8/12`
`⇔x=-2/3`
Vậy `x=-2/3`
`e)(x+3)³-x(3x+1)²+(2x+1)(4x²-2x+1)=28`
`⇔x³+9x²+27x+27-x(9x²+6x+1)+8x³+1=28`
`⇔x³+9x²+27x+27-9x³-6x²-x+8x³+1-28=0`
`⇔(x³-9x³+8x³)+(9x²-6x²)+(27x-x)+(27+1-28)=0`
`⇔3x²+26x=0`
`⇔x(3x+26)=0`
`⇔`\(\left[ \begin{array}{l}x=0\\3x+26=0\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x=0\\x=-\dfrac{26}{3}\end{array} \right.\)
Vậy `x=0` hoặc `x=-26/3`
`f)(x-3)³-(x-3)(x²+3x+9)+6(x+1)²+3x²=-33`
`⇔x³-9x²+27x-27-(x³-27)+6(x²+2x+1)+3x²=-33`
`⇔x³-9x²+27x-27-x³+27+6x²+12x+6+3x²=-33`
`⇔(x³-x³)+(-9x²+6x²+3x²)+(27x+12x)+(-27+27+6)=-33`
`⇔39x+6=-33`
`⇔39x=-33-6`
`⇔39x=-39`
`⇔x=(-39):39`
`⇔x=-1`
Vậy `x=-1`
