Eigenvalues of $\pmatrix{1&1\\1&2}$

Question

I use maxima for calculation eigenvalues of this matrix: $$ \begin{bmatrix} 1 & 1 \\ 1 & 2 \end{bmatrix} $$ and I get $\frac{3\pm\sqrt{5}}{2}$ and then $[1,1]$ for some reason.

Namely:

(%i1) matrix(
 [1,1], 
 [1,2]
);
                                   [ 1  1 ]
(%o1)                              [      ]
                                   [ 1  2 ]
(%i2) eigenvalues(%);
                        sqrt(5) - 3  sqrt(5) + 3
(%o2)               [[- -----------, -----------], [1, 1]]
                             2            2

What does the $[1,1]$ mean? I'm confused.