Aftrekken geeft \(-a=2\text{,}\) dus \(a=-2\text{.}\)

\(\begin{rcases}3a-6b=3 \\ a=-2\end{rcases}\begin{matrix}3⋅-2-6b=3 \\ -6b=9 \\ b=-1\frac{1}{2}\end{matrix}\)

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

\(\begin{cases}6x+4y=3 \\ 2x-2y=-4\end{cases}\) \(\begin{vmatrix}1 \\ 2\end{vmatrix}\) geeft \(\begin{cases}6x+4y=3 \\ 4x-4y=-8\end{cases}\)

Optellen geeft \(10x=-5\text{,}\) dus \(x=-\frac{1}{2}\text{.}\)

\(\begin{rcases}6x+4y=3 \\ x=-\frac{1}{2}\end{rcases}\begin{matrix}6⋅-\frac{1}{2}+4y=3 \\ 4y=6 \\ y=1\frac{1}{2}\end{matrix}\)

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

\(\begin{cases}3p+4q=-5 \\ 4p+6q=-2\end{cases}\) \(\begin{vmatrix}3 \\ 2\end{vmatrix}\) geeft \(\begin{cases}9p+12q=-15 \\ 8p+12q=-4\end{cases}\)

Aftrekken geeft \(p=-11\text{.}\)

\(\begin{rcases}3p+4q=-5 \\ p=-11\end{rcases}\begin{matrix}3⋅-11+4q=-5 \\ 4q=28 \\ q=7\end{matrix}\)

De oplossing is \((p, q)=(-11, 7)\text{.}\)