b,4x mu 2 +4x+1=0 c, 9 mu2 +12x+4=0

0 bình luận về “b,4x mu 2 +4x+1=0 c, 9 mu2 +12x+4=0”

1. b)

   `4x^2+4x+1=0`

   `4x^2+2x+2x+1=0`

   `2x(2x+1)+(2x+1)=0`

   `(2x+1)^2=0`

   `2x+1=0`

   `x=-1/2`

   c)

   `9x^2+12x+4=0`

   `9x^2+6x+6x+4=0`

   `3x(3x+2)+2(3x+2)=0`

   `(3x+2)^2=0`

   `3x+2=0`

   `x=-2/3`

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2. $b,4x² +4x +1= 0$

   $⇒ (2x +1)² = 0$

   $⇒ 2x +1 = 0$

   $⇒ x = \dfrac{-1}{2}$

   $Vậy$ $x = \dfrac{-1}{2}$

   $c, 9x² +12x+4=0$

   $⇒ (3x +2)² = 0$

   $⇒ 3x +2 = 0$

   $⇒ x = \dfrac{-2}{3}$

   $Vậy$ $x = \dfrac{-2}{3}$

    

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