N° 69 page 57 A= entre parenthese 3/4-11/8 fermer la parenthese diviser par ouvrir parenthese 5/3- 7/4 fermer la parenthese. B= 1/4 - 1/5 / 1/5-1/6 C= 2/3- ouvr

bonjour,

A) (3/4-11/8)/(5/3-7/4) =
(6/8-11/8)/(20/12-21/12)=
-5/8 divisé par -1/12 =
-5/8*-12/1 = 60/8  = 15/2

B) 1/4-1/5/1/5 -1/6 =
1/4-1/5*5/1-1/6 =
1/4-1-1/6 =
(3-12-2)/12 = -11/12


C) 2/3-(-4/9+7/6) =
2/3 -(-24+63)/54 =
2/3-(39/54) =
2/3+13/18 =
(12+13)/18 = 25/18 

D) (8/7-6/5)*7/4 - 2 =
-2/35*7/4 - 2 =
-14/140 - 2 =
-1/10 - 20/10 = -21/10

Bonjour,

A = (3/4 - 11/8) : (5/3- 7/4)
A = (3 x 2 / 4 x 2 - 11/8) : (5 x 4 / 3 x 4 - 7 x 3 / 4 x 3)
A = (6/8 - 11/8) : (20/12 - 21/12)
A = - 5/8 x - 1/12
A = - 5/8 x - 12/1
A = 60/8
A = 4 x 15 / 4 x 2
A = 15/2

B = 1/4 - 1/5
       1/5-1/6
B = 1 x 5 / 4 x 5 - 1 x 4 / 5 x 4
      1 x 6 / 5 x 6 - 1 x 5 / 6 x 5
B = 5/20 - 4/20
      6/30 - 5/30
B = 1/20 : 1/30
B = 1/20 x 30/1
B = 30/20
B = 10 x 3 / 10 x 2
B = 3/2

C  = 2/3- (- 4/9+7/6)
C = 2 x 6 / 3 x 6 - (- 4 x 2 / 9 x 2 + 7 x 3 / 6 x 3)
C = 12/18 - (- 8/18 + 21/18)
C = 12/18 - 13/18
C = - 1/18

D = (8/7-6/5) x 7/4-2
D = (8 x 5 / 7 x 5 - 6 x 7 / 5 x 7) x 7/4 - 2
D = (40/35 - 42/35) x 7/4 - 2
D = - 2/35 x 7/4 - 2
D = - 14/140 - 2
D = - 14/140 - 2 x 140 / 1 x 140
D = - 14/140 - 280/140
D = - 266/140
D = 14 x - 19 / 14 x 10
D = - 19/10