Bonjour !
A = 1/4+-3/2 : - 3/5-1/3
=> 1/4+ - 3/2=1/4-6/4 = - 5/4
=> - 3/5-1/3 = - 9/15-5/15 = - 14/15
A =-5/4 : - 14/15 = -5/4×-15/14 = 75/56
B = (-3/4-5/6)×-4/5
(-3/4-5/6)=-18/24-20/24=-38/24=-19/12
B = -19/12-4/5=-95-48/60=-47/60=-7/10
D = (-3/4+5/6) : (-3/2-5/3)
(-3/4+5/6 ) = -18+20/24=2/24=1/12
(-3/2-5/3) = -9-10/6 = - 19/6
D = 1/12 : -19/6= 1/12×-6/19=-6/228=-1/38
C = incompris
Bonne année et bonne journée.