Bonjour,
A=
15/ 42 + (2*2)/ (7*5) =
15/42 + 4/35 =
525/1 470 + 168/1 470 = 593/ 1 470
B=
3/2-1/3 = 9/6 - 2/6 = 7/6
3/4 + 2/3 = 9/12 + 8/12 = 17/12
(7/6)/(17/12) =
(7*12) /( 6*17) = 84/102 = 42/51 = 14/17
C=
-3/14 - (3*5)/7 +2=
-3/14 -15/7 +2=
-3/14 -30/14 + 28/14 =
-5/14
