Răspuns :
6(a-2b+c)-3(2a-4b+c)+5(-a+3b-2c)=6a-12b+6c-6a+12b-3c-5a+15b-10c= 6a-6a-5a-12b+12b+15b+6c-3c-10c= -5a+15b-7c
6(a-2b+c)-3(2a-4b+c)+5(-a+3b-2c)=
6a-12b+6c-6a+12b-3c-5a+15b-10c=
6a-6a-5a-12b+12b+15b+6c-3c-10c= -5a+15b-7c