Tính P(x) + Q(x)

Cho đa thức 
$$\begin{gathered} \mathrm{P}\left(\mathrm{x}\right)={\mathrm{x}}^2-2\mathrm{x}-5{\mathrm{x}}^4+6 \\ \mathrm{Q}\left(\mathrm{x}\right)={\mathrm{x}}^3-5{\mathrm{x}}^4+3{\mathrm{x}}^2-3 \\ \mathrm{Tính} \mathrm{P}\left(\mathrm{x}\right)+\mathrm{Q}\left(\mathrm{x}\right) \end{gathered}$$