I've got to calculate determinant for such matrix:
$$ \begin{bmatrix} a_1+b & a_2 & \cdots & a_n\\ a_1 & a_2+b & \cdots & a_n\\ \vdots & \vdots & \ddots & \vdots\\ a_1 & a_2 & \cdots & a_n+b\\ \end{bmatrix} $$
Please give me some tips how to calculate this.