aidez moi plise juste 2 fraction!! l'exo 3 svp....!!!!!!!

a = 7/6 -1/6 x5
a = 7/6 - 5/6
a = 2/6
a = 1/3

b = 8/3 x(3/2 -1/4)
b = 8/3 x(6/4-1/4)
b = 8/3 x 5/4
b = 40 /12
b = 10/3

encore plus simple que le 2