W obu przykładach masz pomyłki w obliczeniach.
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y = ax + b i A = (- 2, 1), B = (7, 0) ∈ y = ax + b
[tex]\begin{cases} 1 = a \cdot (- 2) + b \\ 0 = a \cdot 7 + b \end{cases} \\\\ \underline{\begin{cases} 1 = - 2a+ b \\ 0 = 7a + b \end{cases}} \ \ \ |- \\\\ 1 - 0 = - 2a - 7a + b - b \\ 1 = - 9a \ \ \ |:(-9) \\ a = - \frac{1}{9} \\\\ 0 = 7a + b \\ 0 = 7 \cdot (- \frac{1}{9}) + b \\ 0= - \frac{7}{9}+b \\ b =\frac{7}{9} \\\\ \begin{cases} a = - \frac{1}{9} \\ b=\frac{7}{9} \end{cases} \\\\ Zatem: \ y = - \frac{1}{9}x + \frac{7}{9}[/tex]
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y = ax + b i A = (3, 6), B = (6, 3) ∈ y = ax + b
[tex]\begin{cases} 6=a \cdot 3 + b \\ 3=a \cdot 6 + b\end{cases} \\\\ \underline{\begin{cases} 6=3a + b \\ 3=6a+ b\end{cases}} \ \ \ |- \\\\ 6-3=3a - 6a + b - b \\ 3 = - 3a \ \ \ |:(- 3) \\ a = - 1 \\\\ 6 = 3a + b \\ 6 = 3 \cdot (-1) + b \\ 6 = - 3 + b \\ b = 6 + 3 \\ b = 9 \\\\ \begin{cases} a=-1 \\ b = 9 \end{cases} \\\\ Zatem: \ y = -x + 9[/tex]
