a) la asta trebuie sa afli lungimea si latimea
P = 2 ( L+ l) = 40 dam
L = 3l => P = 2(3l+l) = 40
2*4l=40 dam
8l = 40 => l = 5 dam(gard viu) => L = 15 dam (prefabricate)
b)m= nr merilor
c= nr ciresilor
m+c= 2500
m-c= 630
_________ (+)
2m / =3130 => m = 1565 => c = 2500- 1565 = 935. ;)