Mathématiques

Question

Aider moi je vous en prie y' a pas beaucoup de choses à faire URGENT URGENT vraiment

Résous les équations suivantes:

1) 7x+1 = - 4-x 2) 3+3x =7-3x 3) 4(x+5) =10x+3 4) 7x-(5x+3) = 5(x-3)+2


5) 7(n+2) -3=25-(3n+4) 6) [tex]x- \frac{5}{4}= \frac{4}{3} [/tex]


merci d' avance je vous donne pleins de points en plus

2 Réponse

  • Si x = 2 alors : 
     7x+1 = 7 x 2 +1 =15 

    4-x2 = 4 - 2 x 2 = 4- 4 = 0

    7-3x3=7-3x2x3= 7- 18 = 11 


  • 1) 7x+1 = -4-x
    => 7x +x = -4-1
    => 8x= -5
    => x= -5/8

    2) 3+3x =7-3x
    => 3-7= -3x-3x
    => -4 = -6x
    => -6x = -4
    => x= -4/-6
    => x = -2/-3 = 2/3

    3) 4(x+5) =10x+3
    => 4x+20 = 10x+3
    => 4x-10x= 3-20
    => -6x= -17
    => x= -17/-6 = 17/6

    4) 7x-(5x+3) = 5(x-3)+2
    => 7x-5x-3 = 5x-15+2
    => 2x-3 = 5x -13
    => 2x -5x = -13+3
    => -3x = -10
    => x= -10/-3 = 10/3

    5) 7(n+2) -3=25-(3n+4)
    => 7n+ 14-3 = 25 -3n -4
    => 7n + 11 = 21- 3n
    => 7n - 3n= 21-11
    => 4n = 10
    => n= 10/4 = 5/2






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