Bonjours pouvez-vous m’aider merci

Réponse :

a = -2/21

b = -5/7

a/b = -2/21 : -5/7 = -2/21 x -7/5 = 14/105 = 2/15

b/a = -5/7 : -2/21 = -5/7 x -21/2 = 105/14 = 15/2

a x b = -2/21 x -5/7 = 10/147

a + b = (-2/21) + (-5/7) = (-2/21) + (-15/21) = -17/21

a - b = (-2/21) - (-5/7) =  -2/21 + 5/7 = -2/21 + 15/21 =       13/21

Explications étape par étape