Bonjour je n’arrive pas mon exo Merci de votre aide 12 pts maths

Bonjour,

A:

5/3 *4/7 = 20/21

2/3 +20/21 =  

14/21 +20/21 = 34/21

B:

(4/3)/ (5/2)

4/3 * 2/5 = 8/15

7/30 - 8/15 =

7/30 - 16/30 = -9/30 = -3/10

C:

4-1/3=  12/3 -4/3  = 8/3

8/3 +5/4 =

32/12 + 15/12 = 4

D:

7/4 -2 = 7/4 - 8/4 = -1/4

5/4 + 3 = 15/12 + 12/4 = 27/4

(-1/4)/(27/4) =

-1/4 * 4/27 = -4/ 108= -1/27

E:

5-2/5 = 25/5 -2/5 = 23/5

4/5*9 = 36/5

(23/5) / (36/5) =

23/5 * 5/36 =

115/ 180  = 23/36

F:

1/3 * 4/8 = 4/24

5/6 + 4/24 + 7/3 =

20/24 + 4/24 + 56/24 =

80/24 = 40/12 = 20/6 = 10/3

Réponse :

Bonjour 2tupac

Explications étape par étape

A = 2/3 +5/3 X 4/7  la multiplication est prioritaire

A = 2/3 +20/21

A = 2/3 X 7/7 +20/21

A = 14/21 +20/21

A = 34/21

B = 7/30 -4/3 : 5/2   la division est prioritaire

B = 7/30 -4/3 X 2/5  la multiplication est prioritaire

B = 7/30 -8/15

B = 7/30 -8/15 X 2/2

B = 7/30 -16/30

B = -9/30 : 3/3 pour simplifier c'est = -3/10

C = (4 - 1/3) + 5/4 le signe devant 5/4 c'est ce que je lis.

C = (4 X 3/3 -1/3) +5/4

C = (12/3 -1/3) +5/4

C = 11/3 +5/4

C = 11/3 X 4/4 +5/4 X 3/3

C = 44/12 +15/12

C = 59/12

D = 7/4 -2 = 7/4 -2 X 4/4 =7/4 -8/4   = -1/4 = -1/4 X 4/17 = -4/ 68 = -1/17

      5/4 +3    5/4 +3 X 4/4   5/4 +12/4    17/4

E = 5 -2/5    = 5 X 5/5 -2/5 = 25/5 -2/5 = 23/5 X 5/36 = 115/180 : 5/5 = 25/56

    4/5 X 9      36/5                  36/5

F = 5/6 +1/3 X 4/8 +7/3

F = 5/6 +4/24 +7/3

F = 5/6 X 4/4 +4/24 +7/3 X 8/8

F = 20/24 +4/24 + 56/24

F = 80/24 = 40/12 = 20/6 = 10/3