bonjour ; vous pouvez m'aider

A = 2/3 -7/3 X 8/21                    la multiplication est prioritaire

A = 2/3 -56/63

A = 42/63 -56/63 = -14/23

B = (3/4 -5/6) X 3/2

B = (18/24 -20/24) X 3/2

B = -2/24 X 3/2

B = -6/48 = -3/24 = -1/8

C = 11 : (2/3 -5/2)

C = 11 : ( 4/6 -15/6)

C = 11 : -11/6 = 11 X 6/-11 = -66/11 = -6

D = 3/7 -15/7 : 5/24

D = 3/7 -15/7 X 24/5

D = 3/7  -360/35

D = 15/35 -360/35 = -345/35 = -69/7

E = ( 11/7 -2/5) X 24/7

E = (55/35 -14/35) X 24/7

E = 41/35 X 24/7 = 984/245

F = 25/15 X (1/18 +1/24)

F = 25/15 X (24/432 + 18/432)

F = 25/15 X 42/432 = 1050/6480 = 105/648 = 35/216