Giải bất phương trình \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciiBaiaac+ % gacaGGNbWaaSbaaSqaamaalaaabaGaaG4maaqaaiaaisdaaaaabeaa % kmaabmaabaaeaaaaaaaaa8qacaaIYaGaamiEaiabgkHiTiaaigdaa8 % aacaGLOaGaayzkaaWdbiabg6da+iaaikdaaaa!4171! {\log _{\frac{3}{4}}}\left( {2x - 1} \right) > 2\) ta được:
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Lời giải:
Báo saiĐiều kiện \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiEaiabg6 % da+maalaaabaGaaGymaaqaaiaaikdaaaaaaa!3980! x > \frac{1}{2}\)
Khi đó bất phương trình tương đương với \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciiBaiaac+ % gacaGGNbWaaSbaaSqaamaalaaabaGaaG4maaqaaiaaisdaaaaabeaa % kmaabmaabaGaaGOmaiaadIhacqGHsislcaaIXaaacaGLOaGaayzkaa % GaeyOpa4JaciiBaiaac+gacaGGNbWaaSbaaSqaamaalaaabaGaaG4m % aaqaaiaaisdaaaaabeaakmaalaaabaGaaGyoaaqaaiaaigdacaaI2a % aaaaaa!4756! {\log _{\frac{3}{4}}}\left( {2x - 1} \right) > {\log _{\frac{3}{4}}}\frac{9}{{16}}\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyi1HSTaaG % OmaiaadIhacqGHsislcaaIXaGaeyipaWZaaSaaaeaacaaI5aaabaGa % aGymaiaaiAdaaaGaeyi1HSTaamiEaiabgYda8maalaaabaGaaGOmai % aaiwdaaeaacaaIZaGaaGOmaaaaaaa!4664! \Leftrightarrow 2x - 1 < \frac{9}{{16}} \Leftrightarrow x < \frac{{25}}{{32}}\) Kết hợp với điều kiện ban đầu ta được \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaaca % aIXaaabaGaaGOmaaaacqGH8aapcaWG4bGaeyipaWZaaSaaaeaacaaI % YaGaaGynaaqaaiaaiodacaaIYaaaaaaa!3D84! \frac{1}{2} < x < \frac{{25}}{{32}}\)