Réponse :
Bonsoir;
Explications étape par étape
A = 5/7 -( 3/2 -5/4 ) = 5/7 -(6/4 -5/4 ) = 5/7 -1/4 = 5x4 /7x4 - 1x7/4x7 =
A = 20/28 -7/28 = 13/28
B = (5/8 -7/4 ) - ( -1/3 -4/3 ) = (5/8 - 14/8) - ( -5/3)
B = -9/8 +5/3 = -9x3/8x3 +5x8/3x8 = -27/24 +40/24
B = 13/24
