Bonjour !
Explications étape par étape:
A = 9/5-2/5x11/4
= 9/5-22/20
= (9x20-22x5)/(5x20)
= (180-110)/100
= 70/100
-> On simplifie : A = 7/10 = 0,7
B = 9^2+(-5+7)(-10)^3
= 81+(-5+7)(-1000)
= 81+5000-7000
= 5081-7000
= -1919
C = -7+54-2,5
= 47-2,5
= 44,5
D = (-10-8)/(4-(-2))
= -18/6
= -3
