Aftrekken geeft \(3b=-9\text{,}\) dus \(b=-3\text{.}\)

\(\begin{rcases}2a+4b=-5 \\ b=-3\end{rcases}\begin{matrix}2a+4⋅-3=-5 \\ 2a=7 \\ a=3\frac{1}{2}\end{matrix}\)

De oplossing is \((a, b)=(3\frac{1}{2}, -3)\text{.}\)

\(\begin{cases}2p+2q=5 \\ 4p-q=-5\end{cases}\) \(\begin{vmatrix}1 \\ 2\end{vmatrix}\) geeft \(\begin{cases}2p+2q=5 \\ 8p-2q=-10\end{cases}\)

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

\(\begin{rcases}2p+2q=5 \\ p=-\frac{1}{2}\end{rcases}\begin{matrix}2⋅-\frac{1}{2}+2q=5 \\ 2q=6 \\ q=3\end{matrix}\)

De oplossing is \((p, q)=(-\frac{1}{2}, 3)\text{.}\)

\(\begin{cases}4a-3b=-2 \\ 6a-5b=5\end{cases}\) \(\begin{vmatrix}5 \\ 3\end{vmatrix}\) geeft \(\begin{cases}20a-15b=-10 \\ 18a-15b=15\end{cases}\)

Aftrekken geeft \(2a=-25\text{,}\) dus \(a=-12\frac{1}{2}\text{.}\)

\(\begin{rcases}4a-3b=-2 \\ a=-12\frac{1}{2}\end{rcases}\begin{matrix}4⋅-12\frac{1}{2}-3b=-2 \\ -3b=48 \\ b=-16\end{matrix}\)

De oplossing is \((a, b)=(-12\frac{1}{2}, -16)\text{.}\)