Aidez moi pour le 117 svp

Le premiere reponse est 146

a = 20/77 : 15/22 = 20/77 x 22/15 = 5x4 /11x7  x 11x2 /5x3 = 4x2 /3x7 = 8/21

b = -0.2 +( 15/48 - 36/48) =  - 2/10 +( -21/48) = -2/10 -7/ 16 = -8/80 -35/80 = -43/80

c =  9/40 - 1/4x7/5 = 9/40 -7/20 = 9/40 -14/40 = -5/40 = -1/8