How can I calculate unknown roots from a matrix

I have two basic matrix, and I try to calculate 'lamda' value according to eigen value problem. I must calculate four different 'lamda' values. My code is in below and the results are so complex. I wanna basic results. What can I do?

A = [ 12 22 33 44 ;
      49 56 68 79 ;
      10 11 12 13 ;
      46 58 64 79 ;]

B =  [15 16 17 18 ;
       44 58 67 71 ;
      10 11 12 13;
      15 16 17 18 ;]


D=zeros(4,4);
syms lamda 
I = eye (4);
D = inv(A)*B-(lamda*I)
solve(det(D) == 0,lamda)

the results are

ans =

root(z^4 + (4855*z^3)/3169 - (1700140947479703230035*z^2)/706682405897585557504 - (713595360956524300343*z)/5653459247180684460032 + 8158275/2826729623590342230016, z, 1)

root(z^4 + (4855*z^3)/3169 - (1700140947479703230035*z^2)/706682405897585557504 - (713595360956524300343*z)/5653459247180684460032 + 8158275/2826729623590342230016, z, 2)

root(z^4 + (4855*z^3)/3169 - (1700140947479703230035*z^2)/706682405897585557504 - (713595360956524300343*z)/5653459247180684460032 + 8158275/2826729623590342230016, z, 3)

root(z^4 + (4855*z^3)/3169 - (1700140947479703230035*z^2)/706682405897585557504 - (713595360956524300343*z)/5653459247180684460032 + 8158275/2826729623590342230016, z, 4)

Answer 1

[Matt J]

A = [ 12 22 33 44 ;
      49 56 68 79 ;
      10 11 12 13 ;
      46 58 64 79 ];
B =  [15 16 17 18 ;
       44 58 67 71 ;
      10 11 12 13;
      15 16 17 18 ];

lambda = eig(B,A)

lambda = 4×1

-2.4812 1.0000 -0.0000 -0.0509

[Merve Ala]

Is it eig(A,B)=?

[Matt J]

I don't see why it would be. Your characteristic equation was,

B-lamda*A=0