Mathématiques

Question

Bonjour pouvez-vous m’aider (équation)
A.3x + 4 = 2x + 9
B.2x + 3 = 3x - 5
C.5x + 8 = 8
D.8 ( 2x + 3 ) = 6x - 2
E.9 (5x + 1 ) = 9 - ( x - 4)

2 Réponse

  • bonjour

    [tex]3 x + 4 = 2 x + 9\\3 x - 2 x = 9 - 4\\x = 5 \\\\2 x + 3 = 3 x - 5\\2 x - 3 x = - 5 - 3\\- x = - 8\\x = 8 \\\\5 x + 8 = 8 \\5 x = 8 - 8 \\5 x = 0 \\x = 0 \\\\16 x + 24 = 6 x - 2 \\16 x - 6 x = - 2 - 24\\10 x = - 26 \\x = - 2.6 \\\\45 x + 9 = 9 - x + 4 \\45 x + x = 9 + 4 - 9 \\46 x = 4\\x = 4/46 \\\\[/tex]

  • Bonjour,

    A. 3x + 4 = 2x + 9
    3x - 2x = 9 - 4
    x = 5

    B. 2x + 3 = 3x - 5
    2x - 3x = - 5 - 3
    - x = - 8
    x = 8

    C. 5x + 8 = 8
    5x = 8 - 8
    5x = 0
    Donc forcément x = 0, x est nul

    D. 8 ( 2x + 3 ) = 6x - 2
    16x + 24 = 6x - 2
    16x - 6x = - 2 -24
    10x = -26
    x = - 26/10
    x = - 2,6

    E. 9 ( 5x + 1 ) = 9 - ( x - 4 )
    45x + 9 = 9 - x + 4
    45x + x = 9 + 4 - 9
    46x = 4
    x = 4/46
    x = 2/23




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