Stelsels

Werk uit

\(\left\{\begin{matrix}-10x+4y=-42\\2y-2x=-12\end{matrix}\right.\)

\(\left\{\begin{matrix}-10x+4y=-42\\2y-2x=-12\end{matrix}\right.\\ \Leftrightarrow \left\{\begin{matrix}-10x+4y=-42\\-2x+2y=-12\end{matrix}\right.\text{(Niet verplichte stap, proper schrijven)}\\ \Leftrightarrow \left\{\begin{array}{c|c|c}-10x+4y=-42& \color{red}{1.} & \color{blue}{1.} \\-2x+2y=-12& \color{red}{-5.} & \color{blue}{-2.} \end{array}\right.\\ \Leftrightarrow \left\{\begin{matrix} \color{red}{\underline{-10x+10x}+4y-10y=-42+60} \\ \color{blue}{-10x+4x\underline{+4y-4y}=-42+24} \end{matrix}\right.\\ \Leftrightarrow \left\{\begin{matrix}-6y=18 \\-6x=-18\end{matrix}\right.\\ \Leftrightarrow \left\{\begin{matrix}y=\frac{18}{-6}=-3 \\x=\frac{-18}{-6}=3\end{matrix}\right.\\ \qquad V=\{(3,-3)\}\)