= \sum\limits_{i = 0}^{n - 1} {a_i \left( {x + a} \right)^i } + \sum\limits_{j = 0}^{n - 1} {\left( \begin{array}{c}
 n \\ 
 j \\ 
 \end{array} \right)a^{n - j} x^j } - \sum\limits_{i = 0}^{n - 1} {a_i x^i } = a \cdot D_a \left( {p\left( x \right)} \right)