Bonjour,
A = -2/3 : 8/5
A = -2/3 x 5/8
A = -10/40
A = -1/4
B = -10-8/4-(-2)
B = -10-2-(-2)
B = -12-(-2)
B = -12+2
B = -10
C = 9² + (-5+7)(-10au cube)
C = 81 + (-10au cube) x (-5) + (-10au cube) x 7
C = 81 + 5 000 + (-7 000)
C = 5 081 - 7 000
C = -1 919
D = -7 + 54 - 2.5
D = 47 - 2.5
D = 44.5