8
100000-81938
6/7 of 280
3/8 of 48
240 of 2/3
3/4-2/3
proba que: C(n+2,r)=C(n,r)+2·C(n,r−1)+C(n,r−2)
C(n+2,r)=C(n,r)+2·C(n,r−1)+C(n,r−2)
2/4-2/3
if a=-3 what is the value of 3a2