Optellen geeft \(6 x = -3 \text{,}\) dus \(x = -\frac{1}{2} \text{.}\)

\(\begin{rcases}5 x + 3 y = 2 \\ x = -\frac{1}{2}\end{rcases} \begin{matrix}5 ⋅ -\frac{1}{2} + 3 y = 2 \\ 3 y = 4\frac{1}{2} \\ y = 1\frac{1}{2}\end{matrix}\)

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

\(\begin{cases}2 a + b = -1 \\ 4 a + 6 b = 6\end{cases}\) \(\begin{vmatrix}6 \\ 1\end{vmatrix}\) geeft \(\begin{cases}12 a + 6 b = -6 \\ 4 a + 6 b = 6\end{cases}\)

Aftrekken geeft \(8 a = -12 \text{,}\) dus \(a = -1\frac{1}{2} \text{.}\)

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

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

\(\begin{cases}4 p - 6 q = -2 \\ 6 p - 5 q = 5\end{cases}\) \(\begin{vmatrix}5 \\ 6\end{vmatrix}\) geeft \(\begin{cases}20 p - 30 q = -10 \\ 36 p - 30 q = 30\end{cases}\)

Aftrekken geeft \(-16 p = -40 \text{,}\) dus \(p = 2\frac{1}{2} \text{.}\)

\(\begin{rcases}4 p - 6 q = -2 \\ p = 2\frac{1}{2}\end{rcases} \begin{matrix}4 ⋅ 2\frac{1}{2} - 6 q = -2 \\ -6 q = -12 \\ q = 2\end{matrix}\)

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