Find values which make a matrix singular Find all the values of c for which the following matrix is singular:
$$\begin{bmatrix} 1 & c & c \\ c & c & c \\ 2 & c & 3 \end{bmatrix}$$
Anyone know how to solve this?

The determinant equals $3c-4c^2+c^3$. Compute it by means of Laplace's algorithm, for instance. Otherwise, use the standard trick for $3 \times 3$ matrices. Hence the matrix is singular when $c=0$. Now you can divide the equation $3c-4c^2+c^3=0$ by $c$, and find the other solutions $c=1$ and $c=3$.
