Bonjour !
8) 50/30 - 13/39 = 5/3 - 1/3 = (5 - 1) / 3 = 4/3
9) 25/35 - 14/49 + 1 = 5/7 - 2/7 + 7/7 = (5 - 2 + 7) / 7 = 10/7
10) 24/8 - 14/12 + 5/6 = (24*3)(8*3) - (14*2)/(12*2) + (5*4)/(6*4) = 72/24 - 28/24 + 20/24 = 64/24 = 8/3
11) 49/56 - (-48)/64 + 5/6 = 7/8 - (-3)/4 + 5/6 = (7*3)/(8*3) - (-3*6)(4*6) + (5*4)/(6*4)
= 21/24 - (-18)/24 + 20/24 = 59/24
12) -5/3 + -21/63 - (-60)/30 = -5/3 + -1/3 - (-2) = -5/3 + -1/3 - (-6)/3 = (-5 - 1 + 6)/3 = 0
J'espère t'avoir aidé. Bon courage !
