Bonsoir Svp j'ai besoin d'aide

1-
m=1/2 S1+1/3 S2+(1-(1/2+1/3) )S3
= 1/2 S1+1/3 S2+1-5/6 S3

2-
S1=1,05 S1
S2=1,05 S2
S3=1,05 S3

m= 1,05/2 S1+1,05/3 S2+1-1,05x5/S3
= 1,05 (1/2 S1+1/3 S2+1-5/6 S3)
= 1,05 m
3-
S1= (S1+30)/S1