Question 376422
[A]={{{(matrix(4,4,a,b,c,d, e,f,g,h, i,j,k,l, m,n,o,p))}}}
Let {{{x}}} be the eigenvalue.
Solve for the determinant of 
[A-Ix]={{{(matrix(4,4,a-x,b,c,d, e,f-x,g,h, i,j,k-x,l, m,n,o,p-x))}}}
.
.
.
You will get a fourth degree polynomial whose 4 roots are the eigenvalues.