Làm đầy đủ các bước giải nha Tìm x biết : d) (4x – 3)(2 – 3x) – 6x(3 – 2x) = 7 + 8x e) x(x^2 -3x + 5 ) – ( x+3)(2-x) = x^3 + x^2 – 6 g) 4x ( 2x – 7 )

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1. d. (4x-3)(2-3x)-6x(3-2x)= 7+8x

   ⇒8x-12$x^{2}$ -6+9x-18x+12$x^{2}$ =7+8x

   ⇒-9x=13

   ⇒x=$\frac{-13}{9}$ 

   e.x($x^{2}$ -3x+5)-(x+3)(2-x)=$x^{3}$ +$x^{2}$ -6

   ⇒$x^{3}$ -$3x^{2}+5x-2x+$x^{2}$ -6+3x= $x^{3}$ +$x^{2}$ -6

   ⇒$-3x^{2}$ +6x=0

   ⇒-3x(x-2)=0

   ⇒\(\left[ \begin{array}{l}-3x=0\\x-2=0\end{array} \right.\) 

   ⇒\(\left[ \begin{array}{l}x=0\\x=2\end{array} \right.\) 

   g. 4x(2x-7)-(3x+1)(2x-3)= 3+12x

   ⇒$8x^{2}$ -28x-$6x^{2}$ +9x-2x+3= 3+12x

   ⇒$2x^{2}$ -33x=0

   ⇒x(2x-33)=0

   ⇒\(\left[ \begin{array}{l}x=0\\2x-33=0\end{array} \right.\) 

   ⇒\(\left[ \begin{array}{l}x=0\\x=33/2\end{array} \right.\) 

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2. d) `(4x-3)(2-3x)-6x(3-2x)=7+8x`

   `⇔8x-6-12x^2+9x-18x+12x^2=7+8x`

   `⇔-9x-6=7`

   `⇔-9x=13`

   `⇔x=-13/9`

   e) `x(x^2-3x+5)-(x+3)(2-x)=x^3+x^2-6`

   `⇔x^3-3x^2+5x-2x-6+x^2+3x=x^3+x^2-6`

   `⇔-3x^2+6x=0`

   `⇔x^2-2x=0`

   `⇔x(x-2)=0`

   `⇔x=0;2`

   f) `4x(2x-7)-(3x+1)(2x-3)=3+12x`

   `⇔8x^2-28x-6x^2-2x+9x+3=3+12x`

   `⇔2x^2-33x=0`

   `⇔2x(x-33/2)=0`

   `⇔x=0;33/2`

    

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