Q.Using Cramer's Rule, solve the system of equations $3x+2y=4$ and $x-3y=5$.

The same D, D_x, D_y procedure applies regardless of the sign or size of the coefficients involved.

Forming $D$

Since $D\neq0$, a unique solution exists.

Forming $D_x$

Forming $D_y$

Solving

$x=\frac{-22}{-11}=2 \qquad y=\frac{11}{-11}=-1$ …

Sign errors while expanding a determinant that has more than one negative entry (e.g. computing $3(-3)-2(1)$ as $-9+2$ instead of $-9-2$) — write each d …