$^nC_r+2.^nC_{r-1}+^nC_{r-2}=?$

Question

$\begin{array}{1 1} =^{n+2}C_{r} \\ =^{n+2}C_{r+1} \\ =^{n+1}C_{r+1} \\ =^{n+1}C_{r} \end{array}$