Aftrekken geeft \(a = -8 \text{.}\)

\(\begin{rcases}3 a - b = -6 \\ a = -8\end{rcases} \begin{matrix}3 ⋅ -8 - b = -6 \\ -b = 18 \\ b = -18\end{matrix}\)

De oplossing is \((a , b) = (-8 , -18) \text{.}\)

\(\begin{cases}2 x + 4 y = 3 \\ x - 3 y = -6\end{cases}\) \(\begin{vmatrix}1 \\ 2\end{vmatrix}\) geeft \(\begin{cases}2 x + 4 y = 3 \\ 2 x - 6 y = -12\end{cases}\)

Aftrekken geeft \(10 y = 15 \text{,}\) dus \(y = 1\frac{1}{2} \text{.}\)

\(\begin{rcases}2 x + 4 y = 3 \\ y = 1\frac{1}{2}\end{rcases} \begin{matrix}2 x + 4 ⋅ 1\frac{1}{2} = 3 \\ 2 x = -3 \\ x = -1\frac{1}{2}\end{matrix}\)

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

\(\begin{cases}5 p - 3 q = 1 \\ 4 p + 2 q = 3\end{cases}\) \(\begin{vmatrix}2 \\ 3\end{vmatrix}\) geeft \(\begin{cases}10 p - 6 q = 2 \\ 12 p + 6 q = 9\end{cases}\)

Optellen geeft \(22 p = 11 \text{,}\) dus \(p = \frac{1}{2} \text{.}\)

\(\begin{rcases}5 p - 3 q = 1 \\ p = \frac{1}{2}\end{rcases} \begin{matrix}5 ⋅ \frac{1}{2} - 3 q = 1 \\ -3 q = -1\frac{1}{2} \\ q = \frac{1}{2}\end{matrix}\)

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