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

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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
e) (x+1)(x+2)(x+5) – x^3- 8x^2 = 27

0 bình luận về “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”

  1. `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`

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