Toán Lớp 9: (1,5a.64 + 44)/(1,5a + 1) = 3,6875(2a + 44)/(a + 1)
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Toán Lớp 9: (1,5a.64 + 44)/(1,5a + 1) = 3,6875(2a + 44)/(a + 1)
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Dkxd:a\# – \dfrac{2}{3};a\# – 1\\
\dfrac{{\left( {1,5a.64 + 44} \right)}}{{1,5a + 1}} = \dfrac{{3,6875\left( {2a + 44} \right)}}{{a + 1}}\\
\Leftrightarrow \dfrac{{96a + 44}}{{\dfrac{3}{2}a + 1}} = \dfrac{{\dfrac{{59}}{8}a + \dfrac{{649}}{4}}}{{a + 1}}\\
\Leftrightarrow \left( {96a + 44} \right)\left( {a + 1} \right) = \left( {\dfrac{3}{2}a + 1} \right)\left( {\dfrac{{59}}{8}a + \dfrac{{649}}{4}} \right)\\
\Leftrightarrow 96{a^2} + 96a + 44a + 44\\
= \dfrac{{177}}{{16}}{a^2} + \dfrac{{1003}}{4}a + \dfrac{{649}}{4}\\
\Leftrightarrow \dfrac{{1359}}{{16}}{a^2} – \dfrac{{443}}{4}a – \dfrac{{473}}{4} = 0\\
\Leftrightarrow 1359{a^2} – 1772a – 1892 = 0\\
\Leftrightarrow \left( {a – 2} \right)\left( {1359a + 946} \right) = 0\\
\Leftrightarrow a = 2;a = \dfrac{{ – 946}}{{1359}}\left( {tmdk} \right)\\
Vậy\,a = 2;a = \dfrac{{ – 946}}{{1359}}
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