Nếu \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqaMDevLHfij5gC1rhimfMBNvxyNvgaCLMB0XfBP1 % wA0n3x7btFETxB9ThxSvMz0HciYGxlXacxYL2zOrxkCrxz4r3EK1hE % 91JmamXvP5wqSXMqHnxAJn0BKvguHDwzZbqefqvATv2CG4uz3bIuV1 % wyUbqedmvETj2BSbqefm0B1jxALjhiov2DaebbnrfifHhDYfgasaac % H8YjY-vipgYlh9vqqj-hEeeu0xXdbba9frFj0-OqFfea0dXdd9vqai % -hGuQ8kuc9pgc9q8qqaq-dir-f0-yqaiVgFr0xfr-xfr-xb9adbaqa % aeGaciGaaiaabeqaamaabaabaaGcbaaeaaaaaaaaa8qadaWdXbWdae % aapeWaaeWaa8aabaWdbiaaikdacaWG4bGaeyOeI0IaaGymaaGaayjk % aiaawMcaaiaabsgacaWG4baal8aabaWdbiaaicdaa8aabaWdbiaad2 % gaa0Gaey4kIipakiabg2da9iaaikdaaaa!5DBB! \int\limits_0^m {\left( {2x - 1} \right){\rm{d}}x} = 2\) thì m có giá trị.

Ta có \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqaMDkvLHfij5gC1rhimfMBNvxyNvgaCLMB0XfBP1 % wA0n3x7btFETxB9ThxSvMz0HciYGxlXacxYL2zOrxkCrxz4r3EK1hE % 91dxSvMz0Hci7ThE951EY0xFTGhiCjxANHgDPWfBLzgD8bcxIv2zP5 % 2EHXwAN5wFnaciMasBGWfxG0aiMacmGWfxG0axL5gz7fgBPDMB9bcx % YL2zOrNl9S3ET1Nx7jtF91sBamXvP5wqSXMqHnxAJn0BKvguHDwzZb % qefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhiov2D % aebbnrfifHhDYfgasaacH8YjY-vipgYlh9vqqj-hEeeu0xXdbba9fr % Fj0-OqFfea0dXdd9vqai-hGuQ8kuc9pgc9q8qqaq-dir-f0-yqaiVg % Fr0xfr-xfr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaaeaa % aaaaaaa8qadaWdXbWdaeaapeWaaeWaa8aabaWdbiaaikdacaWG4bGa % eyOeI0IaaGymaaGaayjkaiaawMcaaiaabsgacaWG4baal8aabaWdbi % aaicdaa8aabaWdbiaad2gaa0Gaey4kIipakiabg2da9maabmaapaqa % a8qacaWG4bWdamaaCaaaleqabaWdbiaaikdaaaGccqGHsislcaWG4b % aacaGLOaGaayzkaaWaaqqaa8aaeaqabeaapeGaamyBaaWdaeaapeGa % aGimaaaacaGLhWoacqGH9aqpcaWGTbWdamaaCaaaleqabaWdbiaaik % daaaGccqGHsislcaWGTbaaaa!8CA4! \int\limits_0^m {\left( {2x - 1} \right){\rm{d}}x} = \left( {{x^2} - x} \right)\left| \begin{array}{l} m\\ 0 \end{array} \right. = {m^2} - m\) nên \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqaMbjvLHfij5gC1rhimfMBNvxyNvga7TxB951EY0 % xFT0wpYWftLzgDYL2zOrxyYj3B3bYE71wFETNm91xlT1Im9adxmvMz % 0jxANHgDHjNCVDhiCXwzMr3wGWLyLDwAUTxySL2zU1xdGaIjG0wpTe % diCXfinaIjG0wpYacxCbsdCvMBKTxySL2zU1hiCjxANHgDUaWexLMB % bXgBcf2CPn2qVrwzqf2zLnharuavP1wzZbItLDhis9wBH5garmWu51 % MyVXgaruWqVvNCPvMCG4uz3bqee0evGueE0jxyaibaieYlNi-xH8yi % VC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9vqaqpepm0xbbG8FasPYRqj0- % yi0dXdbba9pGe9xq-JbbG8A8frFve9Fve9Ff0dmeaabaqaciGacaGa % aeqabaWaaeaaeaaakeaaqaaaaaaaaaWdbiaad2gapaWaaWbaaSqabe % aapeGaaGOmaaaakiabgkHiTiaad2gacqGH9aqpcaaIYaGaeyi1HSTa % amyBa8aadaahaaWcbeqaa8qacaaIYaaaaOGaeyOeI0IaamyBaiabgk % HiTiaaikdacqGH9aqpcaaIWaGaeyi1HS9aamqaa8aaeaqabeaapeGa % amyBaiabg2da9iabgkHiTiaaigdaa8aabaWdbiaad2gacqGH9aqpca % aIYaaaaiaawUfaaaaa!81C5! {m^2} - m = 2 \Leftrightarrow {m^2} - m - 2 = 0 \Leftrightarrow \left[ \begin{array}{l} m = - 1\\ m = 2 \end{array} \right.\)