Z = [0;0;0];
A=[7,-3,6;4, 2, 4; -1,2,0];
I = eye(3);
syms t;
B = A - t .* I;
det(B)
solve(det(B)==0)
linsolve(A-I,Z)

null(A-I)
null(A-4*I)

[V,D] = eig(A)

AT=transpose(A);
BT=AT-t.*I;
det(B);
solve(det(B)==0);
[VT,DT] = eig(AT);