Algebra-Lineares Gleichungssystem-Einsetzverfahren (2)
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Beispiel Nr: 11
$\begin{array}{l}
\text{Gegeben:} \\
a1 \cdot x +b1 \cdot y =c1\\
a2 \cdot x +b2 \cdot y =c2 \\
\\ \text{Gesucht:} \\\text{x und y}
\\ \\ \textbf{Gegeben:} \\
\\
1\frac{1}{5}x -1\frac{1}{3}y =5\frac{1}{3}\\
2\frac{1}{2}x -\frac{1}{4}y = 12\frac{3}{8} \\
\\
\\ \\ \textbf{Rechnung:} \\\begin{array}{l|l}
\begin{array}{l}
I \qquad 1\frac{1}{5} x -1\frac{1}{3} y =5\frac{1}{3}\\
II \qquad 2\frac{1}{2} x -\frac{1}{4} y = 12\frac{3}{8} \\
\text{I nach x auflösen}\\
1\frac{1}{5} x -1\frac{1}{3} y =5\frac{1}{3} \\
1\frac{1}{5} x -1\frac{1}{3} y =5\frac{1}{3} \qquad /+1\frac{1}{3} y\\
1\frac{1}{5} x =5\frac{1}{3} +1\frac{1}{3} y \qquad /:1\frac{1}{5} \\
x =4\frac{4}{9} +1\frac{1}{9} y \\
\text{I in II}\\
2\frac{1}{2} (4\frac{4}{9} +1\frac{1}{9} y ) + -\frac{1}{4} y = 12\frac{3}{8} \\
11\frac{1}{9} +2\frac{7}{9} y -\frac{1}{4} y = 12\frac{3}{8} \qquad / -11\frac{1}{9} \\
+2\frac{7}{9} y -\frac{1}{4} y = 12\frac{3}{8} -11\frac{1}{9} \\
2\frac{19}{36} y = 1\frac{19}{72} \qquad /:2\frac{19}{36} \\
y = \frac{1\frac{19}{72}}{2\frac{19}{36}} \\
y=\frac{1}{2} \\
x =4\frac{4}{9} +1\frac{1}{9} y \\
x =4\frac{4}{9} +1\frac{1}{9} \cdot \frac{1}{2} \\
x=5 \\
L=\{5/\frac{1}{2}\}
\end{array} &
\begin{array}{l}
I \qquad 1\frac{1}{5} x -1\frac{1}{3} y =5\frac{1}{3}\\
II \qquad 2\frac{1}{2} x -\frac{1}{4} y = 12\frac{3}{8} \\
\text{I nach y auflösen}\\
1\frac{1}{5} x -1\frac{1}{3} y =5\frac{1}{3} \\
1\frac{1}{5} x -1\frac{1}{3} y =5\frac{1}{3} \qquad /-1\frac{1}{5} x\\
-1\frac{1}{3} y =5\frac{1}{3} -1\frac{1}{5}x \qquad /:\left(-1\frac{1}{3}\right) \\
y =-4 +\frac{9}{10}x \\
\text{I in II}\\
2\frac{1}{2}x + -\frac{1}{4}(-4 +\frac{9}{10} x ) = 12\frac{3}{8} \\
1 -\frac{9}{40} x -\frac{1}{4} x = 12\frac{3}{8} \qquad / -1 \\
-\frac{9}{40} x -\frac{1}{4} x = 12\frac{3}{8} -1 \\
2\frac{11}{40} x = 11\frac{3}{8} \qquad /:2\frac{11}{40} \\
x = \frac{11\frac{3}{8}}{2\frac{11}{40}} \\
x=5 \\
y =-4 +\frac{9}{10} x \\
y =-4 +\frac{9}{10} \cdot 5 \\
y=\frac{1}{2} \\
L=\{5/\frac{1}{2}\}
\end{array}
\end{array}
\end{array}$