1) x²-3x+2=0 2) 4x²-12x+5=0 GIẢI BẰNG 6 CÁCH ………….. GIÚP MÌNH VS

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1. `1) C1:x²-3x+2=0`

   `<=>(x^2-x)+(-2x+2)=0`

   `<=>x(x-1)-2(x-1)=0`

   `<=>(x-1)(x-2)=0`

   `<=>`\(\left[ \begin{array}{l}x=1\\x=2\end{array} \right.\)

   `C2:x²-3x+2=0`

   `<=>(x^2-2x)+(-x+2)=0`

   `<=>x(x-2)-(x-2)=0`

   `<=>(x-2)(x-1)=0`

   `<=>`\(\left[ \begin{array}{l}x=2\\x=1\end{array} \right.\)

   `C3:x²-3x+2=0`

   `<=>(x^2-1)+(-3x+3)=0`

   `<=>(x-1)(x+1)-3(x-1)=0`

   `<=>(x-1)(x-2)=0`

   `<=>`\(\left[ \begin{array}{l}x=1\\x=2\end{array} \right.\)

   `2)C1: 4x²-12x+5=0`

   `<=>(4x²-2x)+(-10x+5)=0`

   `<=>2x(2x-1)-5(2x-1)=0`

   `<=>(2x-1)(2x-5)=0`

   `<=>`\(\left[ \begin{array}{l}x=\cfrac12\\x=\cfrac52\end{array} \right.\)

   `C2: 4x²-12x+5=0`

   `<=>(4x²-10x)+(-2x+5)=0`

   `<=>2x(2x-5)-(2x-5)=0`

   `<=>(2x-5)(2x-1)=0`

   `<=>`\(\left[ \begin{array}{l}x=\cfrac52\\x=\cfrac12\end{array} \right.\)

   `C3: 4x²-12x+5=0`

   `<=>(4x²-1)+(-12x+6)=0`

   `<=>(2x-1)(2x+1)-6(2x-1)=0`

   `<=>(2x-1)(2x-5)=0`

   `<=>`\(\left[ \begin{array}{l}x=\cfrac12\\x=\cfrac52\end{array} \right.\)

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2. 1) x²-3x+2=0

       x^2-2x-x+2=0

      (x^2-x)-(2x-2)=0

      x(x-1)-2(x-1)=0

      (x-2)(x-1)     =0

   => x-2=0 hoặc x-1=0

         x-2=0 =>x=2

         x-1 = 0 => x=1  

   vậy S={2 ; 1}

   2) 4x²-12x+5=0

       (2x-1)(2x-5)=0

   => 2x-1=0 hoặc 2x-5=0

         2x-1=0 =>x=1/2

         2x-5=0 =>x=5/2  

   vậy S={1/2 ; 5/2}

    

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