(bx3+6)+b+(bx3+6-b):2=79
(3b+6+b+3b+6-b):2=79
(6b+12):2=79
6b+12=2x79
6b+12=158
6b=158-12
6b=146 , impartim la 2 si partea stanga si partea dreapta
3b=73
b=73:3
b= 24,3
