1. Montre que :
R = (3/5 + 2/45) x 9/29 = 1/5
R = (3 x 9 / 5 x 9 + 2/45) x 9/29 = 1/5
R =(27/45 + 2/45) x 9/29 = 1/5
R = 29/45 x 9/29 = 1/5
R = 261/1305 = 1/5
R = 261 x 1 / 261 x 5 = 1/5
R = 1/5 = 1/5
2) Calculer T pour "x" = 3/5
T = 2/5 + "x" x 15/9
T = 2/5 + 3/5 x 15/9
T = 2/5 + 45/45
T = 2 x 9 / 5 x 9 + 45/45
T = 18/45 + 45/45
T = 63/45
T = 9 x 7 / 9 x 5
T= 7/5