Calculer chaque expression en donnant le résultat sous la forme d'une fraction la plus simple possible. A = -5 + 5 x 9 7    21  25 B =  ( 1 - 1 ) : 2 3   5    

A = -5 + 5 x 9 
      7    21  25
A = -5/7 + 45/525
A = - 5 x 75 / 7 x 75 + 45/525
A = - 375/525 + 45/525
A = - 330/525
A = 15 x - 22 / 15 x 35
A = -22/35

B =  ( 1 - 1 ) : 2
          3   5     5
B = (1 x 5 / 3 x 5 - 1 x 3 / 5 x 3) : 2/5
B = (5/15 -3/15) : 2/5
B = 2/15 x 5/2
B = 10/30
B = 10 x 1 / 10 x 3
B = 1/3

C = 5 - 2 x 9 
      4   3   16
C = 5/4 - 18/48
C = 5 x 12 / 4 x 12 - 18/48
C = 60/48 - 18/48
C = 42/48
C = 6 x 7 / 6 x 8
C = 7/8

D = 1 + 14 : 35 
       3     3    12
D = 1/3 + 14/3 x 12/35
D = 1/3 + 168/105
D = 1 x 35 / 3 x 35 + 168/105
D = 35/105 + 168/105
D = 203/105
D = 7 x 29 / 7 x 15
D = 29/15