Va rog ajutorrrr!!! dau coroanaaa

Răspuns:
a+b+c=7
2a+2b+2c=2(a+b+c)=2·7=14
10a+10b+10c=10·7=70
13a+13b+13c+21=13(a+b+c)+21=13·7+21=112
8a+8b+8c-12=8(a+b+c)-12=8·7-12=44
400-5(a+b+c)=400-5·7=400-35=365
6(a+b+c)+100=6·7+100=142