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?

You could also apply Gaussian Elimination to get:
$$
\begin{pmatrix}
1 & c & c \\
0 & c^2 - c & c - c^2 \\
0 & 0 & -c + 3\\
\end{pmatrix}
$$
This matrix is singular if any element on the diagonal is zero, i.e, if:
$$ c^2 - c = 0  \text{ or } -c+3 = 0 $$
which is equivalent to computing the determinant..
