bonsoir on donne a = 2/5 b/3/4 et c = 7/20 calculer ab+c 2a+bc pouvez vous m'aider merci

ab + c

2/5 * 3/4 + 7/20
= 6/20 + 7/20 = 13/20

2 a + bc
4/5 + 3/4 * 7/20
= 4/5 + 21/80
= 64/80 + 21/80 = 85/80 = 17/16

on calcul ab+c
      =2/5 X 3/4 + 7/20
      = 3/10 + 7/20
      = 6+7/20
      = 13/20

2a + bc
     = (2/5)X2 + 3/4 X 7/20
     = 4/5 + 21/80
     = (64 + 21)/80
     = 85/80
     = 17/16