Bonjour
-2/9 - 14/9 x 3/7
= - 2/9 - 42/63
= - 2/9 - (7 x 6) / (7 x 9)
= - 2/9 - 6/9
= - 8/9
-7/3 x (2/5 - 1)
= - 7/3 x [2/5 - (1 x 5) / (1 x 5)]
= - 7/3 x (2/5 - 5/5)
= - 7/3 x (- 3/5)
= 21/15
= (3 x 7) / (3 x 5)
= 7/5
1/4 + 1/5 x 5/4
= (1 x 5) / (4 x 5) + 5/20
= 5/20 + 5/20
= 10/20
= (10 x 1) / (10 x 2)
= 1/2
2/5 + 2 : 5
= 2/5 x 5/2
= 10/10
= 1.
Réponse :
Bonjour,
Explications étape par étape :
A = -2/9 - 14/9 x 3/7
A = - 2/9 - 42/63
A = - 2/9 - (7 x 6) / (7 x 9)
A = - 2/9 - 6/9
A = - 8/9
B = -7/3 x (2/5 - 1)
B = - 7/3 x [2/5 - (1 x 5) / (1 x 5)]
B = - 7/3 x (2/5 - 5/5)
B = - 7/3 x (- 3/5)
B = 21/15
B = (3 x 7) / (3 x 5)
B = 7/5
C = 1/4 + 1/5 x 5/4
C = (1 x 5) / (4 x 5) + 5/20
C = 5/20 + 5/20
C = 10/20
C = (10 x 1) / (10 x 2)
C = 1/2
D = 2/5 + 2 : 5
D = 2/5 x 5/2
D = 10/10
D = 1
Voilà