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calculer en détaillant les étapes ​:
A = 1/7 - 2/3 × 1/7
B = ( -3/5 + 3/4 ) ÷ 2/3
C = ( 1/9 + 2/3 ) ÷ ( 1/4 - 5/6 )




Répondre :

Bonsoir !

Calculer:

A = 1/7 - 2/3 × 1/7= 1/7 - (2x1)/(3x7)= 1/7 - 2/21= (1x3 - 2)/21= 1/21

B = ( -3/5 + 3/4 ) ÷ 2/3= (-3x4+3x5)/(5x4)x 3/2= (-12+15)/20 (3/2)= (3x3)/(20x2)

   = 9/40

C = ( 1/9+2/3 ) ÷ ( 1/4- 5/6 )= (1+2x3)/9 ÷(1x3-5x2)/12= 7/9÷ (-7/12)= -7/9x (12/7)

   = (-7x12)/(9x7)=  - 1/13 x 4= (-1x4)/3= - 4/3 on a simplifié les 7 et (9 et 12).