Aftrekken geeft \(2x=4\text{,}\) dus \(x=2\text{.}\)

\(\begin{rcases}4x-4y=-2 \\ x=2\end{rcases}\begin{matrix}4⋅2-4y=-2 \\ -4y=-10 \\ y=2\frac{1}{2}\end{matrix}\)

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

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

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

\(\begin{rcases}6x+2y=1 \\ x=-1\frac{1}{2}\end{rcases}\begin{matrix}6⋅-1\frac{1}{2}+2y=1 \\ 2y=10 \\ y=5\end{matrix}\)

De oplossing is \((x, y)=(-1\frac{1}{2}, 5)\text{.}\)

\(\begin{cases}2a-4b=-3 \\ 3a+5b=1\end{cases}\) \(\begin{vmatrix}5 \\ 4\end{vmatrix}\) geeft \(\begin{cases}10a-20b=-15 \\ 12a+20b=4\end{cases}\)

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

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

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