Mathématiques

Question

resoudre les equations suivante
1.(-7x +2)(4x -7)=0

2.(-x +2)(2x -1)-(2x -1)=0

3.(2x +1)²-(x +3)²=0

4. 6x² -1=0

1 Réponse

  • Salut,

    1.(-7x +2)(4x -7)=0
    -7x + 2 = 0
    -7x = -2
    7x = 2
    x = 2/7

    4x - 7 = 0
    4x = 7
    x = 7/4

    S = {2/7; 7/4}


    2.(-x +2)(2x -1)-(2x -1)=0
    (2x-1)(-x + 2  - 1 ) = 0
    (2x-1)(-x+1) = 0
    2x - 1 = 0
    2x = 1
    x = 1/2
    -x = -1
    x =1

    S = {1/2; 1}

    3.(2x +1)²-(x +3)²=0

    [(2x+1) - (x+3)][(2x+1 + x + 3] =0
    (2x + 1 - x - 3)(3x + 4) = 0
    (x -2)(3x+4) = 0
    x - 2 = 0
    x = 2
    3x + 4 = 0
    3x = -4
    x = -4/3

    S = {-4/3; 2}

    4. 6x² -1=0

    6x² = 1
    x² = 1/6
    x² - 1/6 = 0
    [tex](x+ \sqrt{\frac{1}{6} } )(x-\sqrt{\frac{1}{6} }) = 0\\ (x+ \frac{1}{ \sqrt{6} } )(x-\frac{1}{ \sqrt{6} } ) = 0\\ (x+ \frac{ \sqrt{6} }{6})(x-\frac{ \sqrt{6} }{6}) = 0 [/tex]

    [tex]x + \frac{ \sqrt{6} }{6}} = 0\\ x = -\frac{ \sqrt{6} }{6}}\\ [/tex]
    [tex]x -\frac{ \sqrt{6} }{6}} = 0\\ x = \frac{ \sqrt{6} }{6}}\\ [/tex]


    Bonne soirée !

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