Réponse :
Explications étape par étape
Bonsoir
A = 1 - 3/4 x 1/5
À = 1 - 3/20
A = 20/20 - 3/20
A = 17/20
B = 1 - 3/4 + 4/5
B = 20/20 - (3 x 5)/(4 x 5) + (4 x 4)/(5 x 4)
B = 20/20 - 15/20 + 16/20
B = 36/20 - 15/20
B = 21/20
C = 1 - 3/4 : 4/5
C = 1 - 3/4 x 5/4
C = 1 - 15/16
C = 16/16 - 15/16
C = 1/16
D = 1 - (3/4 + 1/5)
D = 1 - [(3 x 5)/(4 x 5) + (1 x 4)/(4 x 5)]
D = 1 - (15/20 + 4/20)
D = 20/20 - 19/20
D = 1/20
M = 1 / [1 + 2 / (1 + 1/2)]
M = 1 / [1 + 2/(2/2 + 1/2)]
M = 1 / [1 + 2/(3/2)]
M = 1 / [1 + 2 x 2/3]
M = 1 / [1 + 4/3]
M = 1 / (3/3 + 4/3)
M = 1 / (7/3)
M = 1 x 3/7
M = 3/7