Aftrekken geeft \(-b = 4 \text{,}\) dus \(b = -4 \text{.}\)

\(\begin{rcases}2 a + 3 b = 1 \\ b = -4\end{rcases} \begin{matrix}2 a + 3 ⋅ -4 = 1 \\ 2 a = 13 \\ a = 6\frac{1}{2}\end{matrix}\)

De oplossing is \((a , b) = (6\frac{1}{2} , -4) \text{.}\)

\(\begin{cases}3 x - y = -6 \\ 4 x - 6 y = -1\end{cases}\) \(\begin{vmatrix}6 \\ 1\end{vmatrix}\) geeft \(\begin{cases}18 x - 6 y = -36 \\ 4 x - 6 y = -1\end{cases}\)

Aftrekken geeft \(14 x = -35 \text{,}\) dus \(x = -2\frac{1}{2} \text{.}\)

\(\begin{rcases}3 x - y = -6 \\ x = -2\frac{1}{2}\end{rcases} \begin{matrix}3 ⋅ -2\frac{1}{2} - y = -6 \\ -y = 1\frac{1}{2} \\ y = -1\frac{1}{2}\end{matrix}\)

De oplossing is \((x , y) = (-2\frac{1}{2} , -1\frac{1}{2}) \text{.}\)

\(\begin{cases}2 p + 6 q = -2 \\ 5 p - 5 q = 5\end{cases}\) \(\begin{vmatrix}5 \\ 6\end{vmatrix}\) geeft \(\begin{cases}10 p + 30 q = -10 \\ 30 p - 30 q = 30\end{cases}\)

Optellen geeft \(40 p = 20 \text{,}\) dus \(p = \frac{1}{2} \text{.}\)

\(\begin{rcases}2 p + 6 q = -2 \\ p = \frac{1}{2}\end{rcases} \begin{matrix}2 ⋅ \frac{1}{2} + 6 q = -2 \\ 6 q = -3 \\ q = -\frac{1}{2}\end{matrix}\)

De oplossing is \((p , q) = (\frac{1}{2} , -\frac{1}{2}) \text{.}\)