Bonjour, Pouvez-vous m'aider en calculant ces expressions : a) 5/7 + (-3)/7 * 4/5 b) (5/8 + 9/5) / (1/2 - 7/9) c) (2+1/5) / (3/8) Merci pour votre aide

a) 5/7+(-3)/7 * 4/5=
5/7+(-12/35)=
25/35-12/35=13/35

b) (5/8+9/5)/(1/2-7/9)=
(25/40+72/40)/(9/18-14/18)=
97/40/-5/18=
97/40* - 18/5=-1746/-200=-873/100

c) (2+1/5)/3/8=
(10/5+1/5) / 3/8=
11/5 * 8/3 =88/15

bonjour

a= 5/7 - 12/35
a = 25/35 - 12/35
a = 13/25

b = (25/40 + 72/40) / ( 9/18 - 14/18)
b = 97/40 / - 5/18
b = 97/40 * - 18/5
b = - 1746/200
b = - 873/100

c = ( 10/5 + 1/5) / 3/8
c = 11/5 * 8/3
c = 88/15