Combinatie
\(\left\{\begin{matrix}7x+3y=34\\7y+7x=42\end{matrix}\right.\)
\(\left\{\begin{matrix}7x+3y=34\\7y+7x=42\end{matrix}\right.\\ \Leftrightarrow \left\{\begin{matrix}7x+3y=34\\7x+7y=42\end{matrix}\right.\text{(Niet verplichte stap, proper schrijven)}\\ \Leftrightarrow \left\{\begin{array}{c|c|c}7x+3y=34& \color{red}{1.} & \color{blue}{7.} \\7x+7y=42& \color{red}{-1.} & \color{blue}{-3.} \end{array}\right.\\ \Leftrightarrow \left\{\begin{matrix} \color{red}{\underline{7x-7x}+3y-7y=34-42} \\ \color{blue}{49x-21x\underline{+21y-21y}=238-126} \end{matrix}\right.\\ \Leftrightarrow \left\{\begin{matrix}-4y=-8 \\28x=112\end{matrix}\right.\\ \Leftrightarrow \left\{\begin{matrix}y=\frac{-8}{-4}=2 \\x=\frac{112}{28}=4\end{matrix}\right.\\ \qquad V=\{(4,2)\}\)
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vanhoeckes.be/wiskunde 2025-04-26 07:12:54