Answer
Cramer's rule is not applicable.
Work Step by Step
Use zero for the missing variable.
The given system of equations is
$\left\{\begin{matrix}
-x& +&2y&=&5\\
4x& -&8y & =&6
\end{matrix}\right.$
Determinant $D$ consists of the $x$ and $y$ coefficients.
$D=\begin{vmatrix}
-1&2 \\
4& -8
\end{vmatrix}=(-1)(-8)-(4)(2)=8-8=0$
We have $D=0$ hence, the Cramer's rule is not applicable.
