Let for j = 0,. . ., n aj = a0 + jd, where a0 and d are fixed real numbers.
Calculate the determinant of the matrix A of size (n + 1) × (n + 1). Matrix A is below

What have you done so far to solve this?

I don't know, i kind of got stuck on this one. 

Apply the definition? look at the symmetry, maybe use some known decomposition of this sort of matrix and apply properties of the determinant.. these are just thoughts..

As I don't simply want to give the answer. Once you have the matrix entries and type of matrix figured out.

Follow the following rules to get the determinant

https://www.mathsisfun.com/algebra/matrix-determinant.html