$\displaystyle \binom{n}{k}=\binom{n-1}{k} + \binom{n-1}{k-1}$
$\displaystyle \left(1+x\right)^{n} = \left(1+x\right)\left(1+x\right)^{n-1}$
How do I use binomial expansion on the second equations for the right hand side and convert it to the first equation? The left hand side is obvious, but I'm not sure how to do the right hand side. Please give me some hints
thanks