\[y = x^{2} + a;\ \ \ y = - 4x + 5.\]
\[1)\ Точка\ касания:\]
\[y^{'} = 2x + 0 = 2x;\]
\[k = 2x = - 4\]
\[x = - 2.\]
\[y( - 2) = 8 + 5 = 13;\]
\[y( - 2) = 4 + a.\]
\[2)\ 13 = 4 + a;\]
\[a = 9;\]
\[Ответ:\ \ 9.\]