Tìm hoành độ các giao điểm của đường thẳng \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyEaiabg2 % da9iaaikdacaWG4bGaeyOeI0YaaSaaaeaacaaIXaGaaG4maaqaaiaa % isdaaaaaaa!3CE3! y = 2x - \frac{{13}}{4}\) với đồ thị hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyEaiabg2 % da9maalaaabaGaamiEamaaCaaaleqabaGaaGOmaaaakiabgkHiTiaa % igdaaeaacaWG4bGaey4kaSIaaGOmaaaaaaa!3E3A! y = \frac{{{x^2} - 1}}{{x + 2}}\) .
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Lời giải:
Báo saiHoành độ giao điểm của hai đồ thị hàm số là nghiệm của pt:
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaaca % WG4bWaaWbaaSqabeaacaaIYaaaaOGaeyOeI0IaaGymaaqaaiaadIha % cqGHRaWkcaaIYaaaaiabg2da9iaaikdacaWG4bGaeyOeI0YaaSaaae % aacaaIXaGaaG4maaqaaiaaisdaaaGaeyi1HS9aaiqaaqaabeqaaiaa % dIhacqGHGjsUcqGHsislcaaIYaaabaGaeyOeI0IaaGinaiaadIhada % ahaaWcbeqaaiaaikdaaaGccqGHsislcaaIZaGaamiEaiabgUcaRiaa % ikdacaaIYaGaeyypa0JaaGimaaaacaGL7baacqGHuhY2daGabaabae % qabaGaamiEaiabgcMi5kabgkHiTiaaikdaaeaadaWabaabaeqabaGa % amiEaiabg2da9iaaikdaaeaacaWG4bGaeyypa0JaeyOeI0IaaGPaVp % aalaaabaGaaGymaiaaigdaaeaacaaI0aaaaaaacaGLBbaaaaGaay5E % aaGaeyi1HS9aamqaaqaabeqaaiaadIhacqGH9aqpcaaIYaaabaGaam % iEaiabg2da9iabgkHiTiaaykW7daWcaaqaaiaaigdacaaIXaaabaGa % aGinaaaaaaGaay5waaaaaa!73B4! \frac{{{x^2} - 1}}{{x + 2}} = 2x - \frac{{13}}{4} \Leftrightarrow \left\{ \begin{array}{l} x \ne - 2\\ - 4{x^2} - 3x + 22 = 0 \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} x \ne - 2\\ \left[ \begin{array}{l} x = 2\\ x = - \,\frac{{11}}{4} \end{array} \right. \end{array} \right. \Leftrightarrow \left[ \begin{array}{l} x = 2\\ x = - \,\frac{{11}}{4} \end{array} \right.\)