Find the value of `sum_(0leiltjlen) (C_i+C_j)`

Find the value of sum_(0<=i

sum_(0<=i<=j<=n)^( Find the value of )(i+j)(nC_(i)+nC_(j))

Find the value of sum_(1<=i<=j<=n-1)(ij)^(n)c_(i)^(n)c_(j)

If a_(1),a_(2),a_(3) are the roots of z^(3)-3z^(2)+3z+7=0, then find the value of |sum_(i!=j)((a_(i)-1)/(a_(j)-1))|