Bonsoir qui peut m'aider pour l'exercice 49 Merci d'avance

a= (18/5)×(35/8 )= ((9×2)/5)×((7×5)/(4×2)) = *9×2×7×5)/(5×4×2 )= (9×7)/4 = 63/4

b = (21/4)×(5/14) = ((7×3)/4)×(5/(7×2))= (3×5)/(4×2) = 35/8


c = (20/9)×(9/50) = (10×2×9)/(9×5×10) = 2/5

18/5 * 35/8= 9*2/5 * 5*7/4*2= 9/1 * 7/4 =9*7/4= 63/4

21/4 * 5/14= 21*5/4*14= 105/296