How to obtain the eigenvalues when I get the warning that the matrix is singular?

How can I obtain the row reduction method to get the values for Lamda?

% A
I = eye(2)
m1 = [7 3; 3 -1]
Lamda = 8                   % The value for λ
% B
LaI = I * Lamda            % Identity matrix - value of λ
m2s = m1 - LaI            % Caluculating the new matrix
% C
zc = zeros(size(m2s,1),1)     % creating a zero column
m3s = [m2s, zc]                     % adding the zero column at the end

I tried to use the forward an backward passing method, but there I only get the warning that the matrix is singular.

Answer 1

[Walter Roberson]

% A
I = eye(2)

I = 2×2

1 0 0 1

m1 = [7 3; 3 -1]

m1 = 2×2

7 3 3 -1

syms Lamda                   % The value for λ
% B
LaI = I * Lamda            % Identity matrix - value of λ

LaI = 

m2s = m1 - LaI            % Caluculating the new matrix

m2s = 

d = det(m2s)

d = 

eigens = solve(d)

eigens =