Gọi \(S_1,S_2,S_3\) lần lượt là tập nghiệm của các bất phương trình sau: \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaGOmamaaCa % aaleqabaGaamiEaaaakiabgUcaRiaaikdacaGGUaGaaG4mamaaCaaa % leqabaGaamiEaaaakiabgkHiTiaaiwdadaahaaWcbeqaaiaadIhaaa % GccqGHRaWkcaaIZaGaeyOpa4JaaGimaaaa!4265! {2^x} + {2.3^x} - {5^x} + 3 > 0\) \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciiBaiaac+ % gacaGGNbWaaSbaaSqaaiaaikdaaeqaaOWaaeWaaeaacaWG4bGaey4k % aSIaaGOmaaGaayjkaiaawMcaaiabgsMiJkabgkHiTiaaikdaaaa!4137! ;{\log _2}\left( {x + 2} \right) \le - 2\) \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaeWaaeaada % WcaaqaaiaaigdaaeaadaGcaaqaaiaaiwdaaSqabaGccqGHsislcaaI % XaaaaaGaayjkaiaawMcaamaaCaaaleqabaGaamiEaaaakiabg6da+i % aaigdaaaa!3DCA! ; {\left( {\frac{1}{{\sqrt 5 - 1}}} \right)^x} > 1\).Tìm khẳng định đúng?

Bất phương trình \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaGOmamaaCa % aaleqabaGaamiEaaaakiabgUcaRiaaikdacaGGUaGaaG4mamaaCaaa % leqabaGaamiEaaaakiabgkHiTiaaiwdadaahaaWcbeqaaiaadIhaaa % GccqGHRaWkcaaIZaGaeyOpa4JaaGimaaaa!4265! {2^x} + {2.3^x} - {5^x} + 3 > 0\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyi1HS9aae % WaaeaadaWcaaqaaiaaikdaaeaacaaI1aaaaaGaayjkaiaawMcaamaa % CaaaleqabaGaamiEaaaakiabgUcaRiaaikdacaGGUaWaaeWaaeaada % WcaaqaaiaaiodaaeaacaaI1aaaaaGaayjkaiaawMcaamaaCaaaleqa % baGaamiEaaaakiabgUcaRiaaiodacaGGUaWaaeWaaeaadaWcaaqaai % aaigdaaeaacaaI1aaaaaGaayjkaiaawMcaamaaCaaaleqabaGaamiE % aaaakiabg6da+iaaigdaaaa!4B8B! \Leftrightarrow {\left( {\frac{2}{5}} \right)^x} + 2.{\left( {\frac{3}{5}} \right)^x} + 3.{\left( {\frac{1}{5}} \right)^x} > 1\)

Ta thấy VT nghịch biến mà f(2) = 1 nên f(x) > f(2) \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyi1HSTaam % iEaiabgYda8iaaikdacqGHshI3caWGtbWaaSbaaSqaaiaaigdaaeqa % aOGaeyypa0ZaaeWaaeaacqGHsislcqGHEisPcaGG7aGaaGOmaaGaay % jkaiaawMcaaaaa!459A! \Leftrightarrow x < 2 \Rightarrow {S_1} = \left( { - \infty ;2} \right)\)

Bất phương trình \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciiBaiaac+ % gacaGGNbWaaSbaaSqaaiaaikdaaeqaaOWaaeWaaeaacaWG4bGaey4k % aSIaaGOmaaGaayjkaiaawMcaaiabgsMiJkabgkHiTiaaikdaaaa!4137! {\log _2}\left( {x + 2} \right) \le - 2\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyi1HSTaaG % imaiabgYda8iaadIhacqGHKjYOcqGHsisldaWcaaqaaiaaiEdaaeaa % caaI0aaaaaaa!3F3B! \Leftrightarrow 0 < x \le - \frac{7}{4}\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyO0H4Taam % 4uamaaBaaaleaacaaIYaaabeaakiabg2da9maajadabaGaeyOeI0Ia % aGOmaiaacUdacqGHsisldaWcaaqaaiaaiEdaaeaacaaI0aaaaaGaay % jkaiaaw2faaaaa!41F6! \Rightarrow {S_2} = \left( { - 2; - \frac{7}{4}} \right]\)

Bất phương trình \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaeWaaeaada % WcaaqaaiaaigdaaeaadaGcaaqaaiaaiwdaaSqabaGccqGHsislcaaI % XaaaaaGaayjkaiaawMcaamaaCaaaleqabaGaamiEaaaakiabg6da+i % aaigdaaaa!3DCA! {\left( {\frac{1}{{\sqrt 5 - 1}}} \right)^x} > 1\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyi1HS9aae % WaaeaadaWcaaqaaiaaigdaaeaadaGcaaqaaiaaiwdaaSqabaGccqGH % sislcaaIXaaaaaGaayjkaiaawMcaamaaCaaaleqabaGaamiEaaaaki % abg6da+maabmaabaWaaSaaaeaacaaIXaaabaWaaOaaaeaacaaI1aaa % leqaaOGaeyOeI0IaaGymaaaaaiaawIcacaGLPaaadaahaaWcbeqaai % aaicdaaaaaaa!4532! \Leftrightarrow {\left( {\frac{1}{{\sqrt 5 - 1}}} \right)^x} > {\left( {\frac{1}{{\sqrt 5 - 1}}} \right)^0}\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyi1HSTaam % iEaiabgYda8iaaicdacqGHshI3caWGtbWaaSbaaSqaaiaaiodaaeqa % aOGaeyypa0ZaaeWaaeaacqGHsislcqGHEisPcaGG7aGaaGimaaGaay % jkaiaawMcaaaaa!4598! \Leftrightarrow x < 0 \Rightarrow {S_3} = \left( { - \infty ;0} \right)\)

Ta thấy \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uamaaBa % aaleaacaaIYaaabeaakiabgkOimlaadofadaWgaaWcbaGaaG4maaqa % baGccqGHckcZcaWGtbWaaSbaaSqaaiaaigdaaeqaaaaa!3F3F! {S_2} \subset {S_3} \subset {S_1}\)