Write a Maple code that performs a process similar to the Gaussian elimination for an n times n matrix that we did in class, where we converted it to an upper triangular matrix, but his lime converting it to a lower triangular matrix. b) Test your code for the 4 times 4 matrix we used for the class example: A = [3 4 1 2 -1 2 0 -2 1 1 2 -1 2 -3 1 0]