Giải các hệ : $\begin{array}{l} 1)\,\,\,\left\{ \begin{array}{l} {y^{1 - \frac{2}{5}{{\log }_x}y}} = {x^{\frac{2}{5}}}\\ 1 + {\log _x}\left( {1 - \frac{{3y}}{x}} \right) = {\log _x}4 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(1)\\ 2)\,\,\,\left\{ \begin{array}{l} y.{x^{{{\log }_y}x}} = {x^{\frac{5}{2}}}\\ {\log _4}y.{\log _y}\left( {y - 3x} \right) = 1 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2) \end{array}$
Đăng bài 26-04-12 04:39 PM
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Giải và biện luận theo $a$ hệ sau : $\left\{ \begin{array}{l} 2cos\,x + sin\,x = 1\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(1)\\ {\log _z}\sin y = {\log _z}a.{\log _a}\left( {2 - 3cos\,x} \right)\,\,\,\,\,\,\,(2)\\ {\log _a}z + {\log _a}\left( {\frac{1}{{2a}} - 1} \right) = 0\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(3) \end{array} \right.$
Đăng bài 08-05-12 04:39 PM
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Giải các hệ phương trình: $1)\,\,\left\{ \begin{array}{l} xy = 40\\ {x^{\lg y}} = 4 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,2)\,\,\left\{ \ \begin{array}{l} {\log _y}x + {\log _x}y = 2\\ {x^2} + y = 12 \end{array} \right.$
Đăng bài 08-05-12 03:22 PM
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Giải các hệ : $1)\,\left\{ \begin{array}{l} {3^x}{.2^y} = \frac{1}{9}\\ y - x = 2 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,2)\,\left\{ \begin{array}{l} {2^y} = {200.5^x}\\ x + y = 1 \end{array} \right.$
Đăng bài 08-05-12 03:00 PM
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Giải hệ phương trình : $\left\{ \begin{array}{l} {\log _x}\left( {3x + 2y} \right) = 2\\ {\log _y}\left( {2x + 3y} \right) = 2 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(1)$
Đăng bài 08-05-12 03:16 PM
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Giải các hệ : $\begin{array}{l} 1)\,\,\,\left\{ \begin{array}{l} \left( {1 + 2{{\log }_{\left| {xy} \right|}}2} \right).{\log _{x + y}}\left| {xy} \right| = 1\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(1)\\ x - y = 2\sqrt {3\,} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2) \end{array} \right.\\ 2)\,\,\,\left\{ \begin{array}{l} {\log _{\left| {xy} \right|}}\left( {x - y} \right) = 1\\ 2{\log _5}\left| {xy} \right|.{\log _{\left| {xy} \right|}}\left( {x + y} \right) = 1 \end{array} \right. \end{array}$
Đăng bài 26-04-12 04:34 PM
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Giải các hệ phương trình : $\begin{array}{l} 1)\,\,\left\{ \begin{array}{l} {\log _2}\left( {{x^2} + {y^2}} \right) = 5\\ 2{\log _4}x + {\log _2}y = 4 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,3)\,\,\,\left\{ \begin{array}{l} {3^{\lg x}} = {4^{\lg y}}\\ {\left( {4x} \right)^{\lg 4}} = {\left( {3y} \right)^{\lg 3}} \end{array} \right.\\ 2)\,\,\left\{ \begin{array}{l} {3^{{x^2} + {y^2}}} = 81\\ {\log _2}x + 2{\log _4}y = 1 \end{array} \right. \end{array}$
Đăng bài 08-05-12 03:12 PM
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Giải các hệ : $1)\,\,\,\left\{ \begin{array}{l} {\log _2}xy = 5\\ {\log _{\frac{1}{2}}}\frac{x}{y} = 1 \end{array} \right.\,\,\,\,\,(1)\,\,\,\,\,\,\,\,\,\,\,\,2)\,\,\,\,\left\{ \begin{array}{l} xy = 64\\ {\log _x}y = 5 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2)$
Đăng bài 08-05-12 03:14 PM
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Đăng bài 14-05-12 04:11 PM
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Đăng bài 11-05-12 01:32 PM
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Đăng bài 12-05-12 10:13 AM
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Đăng bài 08-05-12 03:39 PM
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Đăng bài 17-05-12 09:10 AM
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Giải các hệ : $\begin{array}{l} 1)\,\,\,\left\{ \begin{array}{l} {\log _{2 - x}}\left( {2 - y} \right) > 0\\ {\log _{4 - y}}\left( {2x - 2} \right) > 0 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,3)\,\,\left\{ \begin{array}{l} {\log _{x - 2}}\left( {2y - 4} \right) > 0\\ {\log _{3 - y}}\left( {x - 4} \right) > 0 \end{array} \right.\\ 2)\,\,\,\left\{ \begin{array}{l} {\log _{x - 1}}\left( {5 - y} \right) < 0\\ {\log _{2 - y}}\left( {4 - x} \right) < 0 \end{array} \right. \end{array}$
Đăng bài 08-05-12 03:57 PM
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Giải các hệ : $\begin{array}{l} 1)\,\,\,\left\{ \begin{array}{l} {y^{1 - \frac{2}{5}{{\log }_x}y}} = {x^{\frac{2}{5}}}\\ 1 + {\log _x}\left( {1 - \frac{{3y}}{x}} \right) = {\log _x}4 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(1)\\ 2)\,\,\,\left\{ \begin{array}{l} y.{x^{{{\log }_y}x}} = {x^{\frac{5}{2}}}\\ {\log _4}y.{\log _y}\left( {y - 3x} \right) = 1 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2) \end{array}$
Đăng bài 08-05-12 03:43 PM
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