A = (2 + 5/3) * ( 3 - 4/5)
= 6+5 * 15 - 4 = 11/3 * 11/5 = 121/15
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3 5
B = 3*5/6 - 4*6/3 + 3/2
= 15/6 - 24/3 + 3/2
= (15 - 48 + 9) / 6
= -24/6 = -4
C= -8*-3/3*7 - 4/14 - 11/7 = 8/7 - 2/7 - 11/4 = (8-2-11)/7 = -5/7
Voilà, n'hésite pas si t'as des questions