a, \(\left{\right. � - 2 \neq 0 \Leftrightarrow � \neq 2 \\ � + 2 \neq 0 \Leftrightarrow � \neq - 2\)

\(� , � = \frac{�^{2}}{�^{2} - 4} - \frac{�}{� - 2} - \frac{2}{� + 2} = \frac{�^{2}}{\left(\right. � - 2 \left.\right) \left(\right. � + 2 \left.\right)} - \frac{�}{� - 2} - \frac{2}{� + 2} = \frac{�^{2} - � \left(\right. � + 2 \left.\right) - 2 \left(\right. � - 2 \left.\right)}{\left(\right. � - 2 \left.\right) \left(\right. � + 2 \left.\right)} = \frac{�^{2} - �^{2} - 2 � - 2 � + 4}{\left(\right. � - 2 \left.\right) \left(\right. � + 2 \left.\right)} = \frac{- 4 � + 4}{� - 4}\)

\(� ,\) Để \(� = 2\) ta có

 \(\frac{- 4 � + 4}{� - 4} = 2 \left(\right. � \neq 4 \left.\right) \Leftrightarrow \frac{- 4 � + 4}{� - 4} = \frac{2 \left(\right. � - 4 \left.\right)}{� - 4} \Leftrightarrow - 4 � + 5 = 2 � - 8 \Leftrightarrow - 6 � = - 13 \Leftrightarrow � = \frac{13}{6}\)

Xóa