If $x$ is real and $A=\left[\begin{array}{ccc}1 & -1 & x \ 1 & x & 1 \ x & -1 & 1\end{array} ight

Question

If $x$ is real and $A=\left[\begin{array}{ccc}1 & -1 & x \ 1 & x & 1 \ x & -1 & 1\end{array}ight]$ has no inverse, then $x$ is equal to

Professor PC Thomas Classes · Answer

Determinant equal to zero yields $x=1$.