Mathématiques

Question

Aide please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Aide please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Aide please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

1 Réponse

  • A = 1/5 x - 4/3 + 7/2
    A = - 4/15 + 7/2
    A = - 4 x 2 / 15 x 2 + 7 x 15 / 2 x 15
    A = - 8/30 + 105/30
    A = 75/30
    A = 15 x 5 / 15 x 2
    A = 5/2

    B = 4/5 : (- 3/7) - 7/10
    B = 4/5 x - 7/3 - 7/10
    B = - 28/15 - 7/10
    B = - 28 x 10 / 15 x 10 - 7 x 15 / 10 x 15
    B = - 280/150 - 105/150
    B = 385/105
    B = 35 x 11 / 35 x 3
    B = 11/3

    C = 13/7 + (- 8/7) : (-4/5)
    C = 13/7 + (-8/7) x (- 5/4)
    C = 13/7 + 40/28
    C = 13 x 4 / 7 x 4 + 40/28
    C = 52/28 + 40/28
    C = 92/28
    C = 4 x 23 / 4 x 7
    C = 23/7

    D = 7/3 + 3/2 x - 10/21
    D = 7/3 - 30/42
    D = 7 x 14 / 3 x 14 - 30/42
    D = 98/42 - 30/42
    D = 68/42
    D = 2 x 34 / 2 x 21
    D = 34/21

    E = 5/8 + (- 3/4) : (- 9/16)
    E = 5/8 + (- 3/4) x (- 16/9)
    E = 5/8 + 48/36
    E = 5 x 36 / 8 x 36 + 48 x 8 / 36 x 8
    E = 180/288 + 384/288
    E = 564/288
    E = 12 x 47 / 12 x 24
    E = 47/24

    F = 6/5 - (- 1/9) x (- 3/4)
    F = 6/5 - (3/36)
    F = 6 x 36 / 5 x 36 - 3 x 5 / 36 x 5
    F = 216/180 - 15/180
    F = 201/180
    F = 3 x 67 / 3 x 60
    F = 67/60


    a) 3x² + 5x - 3 = 6x + 1
    Pour x = 4/3

    3 * 4²/3² + 5 * 4/3 - 3 = 6 * 4/3 + 1
    3 x 16/9 + 20/3 - 3 = 24/3 + 1
    48/9 + 20/3 - 3 = 24/3 + 1
    48/9 + 20 x 2 / 3 x 3 = 24 x 3 / 3 x 3 + 1 x 9 / 1 x 9
    48/9 - 40/9 = 72/9 + 9/9
    8/9 ≠ 81/9
    L'égalité est fausse

    b) x - 1 = - 3x + 2
       2x + 5       x - 3
    Pour x = - 1/4

    - 1/4 - 1        = - 3 * - 1/4 + 2
    2 * -1/4 + 5      - 1/4 - 3
    - 1/4 - 1 x 4 / 1 x 4 = 3/4 + 2 x 4 / 1 x 4
    - 2/4 + 5 x 4 / 1 x 4  - 1/4 - 3 x 4 / 1 x 4
    = - 1/4 - 4/4    = 3/4 + 8/4
       - 2/4 + 20/4    - 1/4 - 12/4
    = - 3/4 11/4
         18/4   11/4
    L'égalité est fausse