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

\(\begin{rcases}3 a - 3 b = 3 \\ a = 8\end{rcases} \begin{matrix}3 ⋅ 8 - 3 b = 3 \\ -3 b = -21 \\ b = 7\end{matrix}\)

De oplossing is \((a , b) = (8 , 7) \text{.}\)

\(\begin{cases}6 a - b = -5 \\ 4 a + 4 b = 6\end{cases}\) \(\begin{vmatrix}4 \\ 1\end{vmatrix}\) geeft \(\begin{cases}24 a - 4 b = -20 \\ 4 a + 4 b = 6\end{cases}\)

Optellen geeft \(28 a = -14 \text{,}\) dus \(a = -\frac{1}{2} \text{.}\)

\(\begin{rcases}6 a - b = -5 \\ a = -\frac{1}{2}\end{rcases} \begin{matrix}6 ⋅ -\frac{1}{2} - b = -5 \\ -b = -2 \\ b = 2\end{matrix}\)

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

\(\begin{cases}3 p + 5 q = -4 \\ 4 p + 3 q = 2\end{cases}\) \(\begin{vmatrix}3 \\ 5\end{vmatrix}\) geeft \(\begin{cases}9 p + 15 q = -12 \\ 20 p + 15 q = 10\end{cases}\)

Aftrekken geeft \(-11 p = -22 \text{,}\) dus \(p = 2 \text{.}\)

\(\begin{rcases}3 p + 5 q = -4 \\ p = 2\end{rcases} \begin{matrix}3 ⋅ 2 + 5 q = -4 \\ 5 q = -10 \\ q = -2\end{matrix}\)

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