Mathématiques

Question

Bonsoir j'aimerais bien que vous m'aidiez as fair l'exercice 1 et 2 svp ​
Bonsoir j'aimerais bien que vous m'aidiez as fair l'exercice 1 et 2 svp ​

1 Réponse

  • Bonjour

    1)

    A = 2/3 + 5/3 x 1/15

    A = 2/3 + 5/45

    A = (2 x 3) / (3 x 3) + (5 x 1) / (5 x 9)

    A = 3/9 + 5/9

    A = 8/9

    B = (1 - 3/7) : 12/5

    B = [(1 x 7) / (1 x 7) - 3/7] : 12/5

    B = (7/7 - 3/7) : 12/5

    B = 4/7 : 12/5

    B = 4/7 x 5/12

    B = 20/84

    B = (4 x 5) / (4 x 21)

    B = 5/21

    C = 9/2 : 3

    C = 9/2 x 1/3

    C = 9/6

    C = (3 x 3) / (3 x 2)

    C = 3/2

    D = (3/4 + 3) : (1/2 + 2)

    D = [3/4 + (3 x 4) / (1 x 4)] : [1/2 + (2 x 2) / (1 x 2)]

    D = (3/4 + 12/4) : (1/2 + 4/2)

    D = 15/4 : 5/2

    D = 15/4 x 2/5

    D = 30/20

    D = (10 x 3) / (10 x 2)

    D = 3/2

    2)

    a. 2/5 + 1

    = 2/5 + (1 x 5) / (1 x 5)

    = 2/5 + 5/5

    = 7/5

    b. 3/4 x 2/5

    = 6/20

    = (2 x 3) / (2 x 10)

    = 3/10

    c. 1/3 x 2/5 + 2/5

    = 2/15 + (2 x 3) / (5 x 3)

    = 2/15 + 6/15

    = 8/15

    d. 3/5 : 2/5

    = 3/5 x 5/2

    = 15/10

    = (5 x 3) / (5 x 2)

    = 3/2

    e. (3/2 - 10/6) : (2/7 + 1/3)

    = [(3 x 3) / (2 x 3) - 10/6] : [(2 x 3) / (7 x 3) + (1 x 7) / (3 x 7)]

    = (9/6 - 10/6) : (6/21 + 7/21)

    = - 1/6 : 13/21

    = - 1/6 x 21/13

    = - 21/78

    = (3 x - 7) / (3 x 26)

    = - 7/26

    f. 3 - 5 : (1 + 1/3)

    = 3 - 5 : [(1 x 3) / (1 x 3) + 1/3]

    = 3 - 5 : (3/3 + 1/3)

    = 3 - 5 : 4/3

    = 3 - 5 x 3/4

    = (3 x 4) / (1 x 4) - 15/4

    = 12/4 - 15/4

    = - 3/4.