Mathématiques

Question

RÉSOLOUS LES ÉQUATIONS SUIVANTES:

a. (5x+1) (8-x) = 0
b. (3x-1) + (7-x) = 0
c. (8+3x) - (x+3) = 0
d. (3-10x) (x+23) = 0
e. 6(y+3) - 2(y-1) = 0

1 Réponse

  • Bonsoir,

    a. (5x+1) (8-x) = 0
    5x + 1 = 0            ou             8 - x = 0
    5x = - 1                ou             x = - 8
    x = - 1/5

    b. (3x-1) + (7-x) = 0
    3x - 1 + 7 - x = 0
    3x - x = 1 - 7
    2x = - 5
    x = - 5/2
    x = - 2,5

    c. (8+3x) - (x+3) = 0
    8 + 3x - x - 3 = 0
    3x - x = - 8 + 3
    2x = - 6
    x = - 6/2
    x = - 3

    d. (3-10x) (x+23) = 0
    - 10 + 3x = 0              ou               x + 23 = 0
    3x = 10                      ou               x = - 23
    x = 10/3            

    e. 6(y+3) - 2(y-1) = 0
    6y + 18 - 2y + 2 = 0
    6y - 2y = - 18 - 2
    4y = - 20
    y = - 20/4
    y = - 5

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