Tìm x, biết: a) (x-2)(x-1) = x(2x+1) + 2 b) (x+2)(x+2) – (x-2)(x-2) = 8x c) (2x-1)(x^2-x+1) = 2x^3 – 3x^2 + 2 d) (x+1)(x^2+2x+4) – x3 – 3x^2 + 16 = 0

`a) (x-2)(x-1) = x(2x+1) + 2`

`=>x^2-2x-x+2-2x^2-x-2=0`

`=>-x^2-4x=0`

`=>`\(\left[ \begin{array}{l}x=0\\x=-4\end{array} \right.\) 

`b) (x+2)(x+2) – (x-2)(x-2) = 8x`

`=>x^2+4x+4-(x^2-4x+4)-8x=0`

`=>(x^2-x^2)+(4x+4x)-+4-4-8x=0`

`=0x=0`

`=>` Pt có vô số nghiệm

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

`=>2x^3-2x^2+2x-x^2+x-1-2x^3+3x^2-2=0`

`=>(2x^3-2x^23)+(-2x^2-x^2+3x^2)+(2x+x)-3=0`

`=>x=3/3=1`

`d) (x+1)(x^2+2x+4) – x^3 – 3x^2 + 16 = 0`

`=>x^3+2x^2+4x+x^2+2x+4-x^3-3x^2+16=0`

`=>(x^3-x^3)+(3x^2-3x^2)+6x+20=0`

`=>x=-20/6=-10/3`

`e) (x+1)(x+2)(x+5) – x^3- 8x^2 = 27`

`=x^3+8x^2+17x+10-x^3-8x^2-27=0`

`=>17x-17=0`

`=>x=1`