33)
C(n,1)= combinari de n luate cate 1.
''*''=inmultit
''!''=factorial
C(n,1) + C(n,2)=120
(n!)/((n-1)! *1!) +(n!)/((n-2)! *2!) =120
n+n(n-1)/2=120
n+(n^2 -n)/2 =120, inmultim cu 2
2n+n^2-n=240
n^2+n-240=0
(n-15)(n+16)=0
n=nr.nat, rezulta n+16>0
Doar n-15=0
n=15
