bonjour,
remplace par les valeurs données
A = x + y + Z
= 6/5 + (-1/24) + (-7/12)
= 6/5 -1/24 -7/12
tt sous deno commun 120
= (144-5-70)/120 = 69/120 =23/40
B = x - y + Z
= 6/5 -(-1/24) + (-7/12)
= 6/5 +1/24 -7/12
= tu finis
C = x-(y+z)
= 6/5-(-1/24-7/12)
= 6/5-(-1-14)/24
= 6/5 -(-15/24)
= 6/5 + 15/24
= tu finis