#1
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$2^{2x+2}-6^x-2(3^{2x+2})=0$ ¨§ËÒ¤èҢͧ $x$
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#2
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$2^{2x+2}-6^x-2(3^{2x+2})=0$
$4 \bullet 2^{2x}-3^x2^x-18(3^{2x})=0$ $(4\bullet 2^x - 9\bullet 3^x)( 2^x + 2\bullet 3^x) = 0$ ¨ÐàËç¹ÇèÒ $4\bullet 2^x - 9\bullet 3^x = 0$ à·èÒ¹Ñé¹ $4\bullet 2^x = 9\bullet 3^x$ $(\frac{2}{3})^x = \frac{9}{4}$ $(\frac{2}{3})^x = (\frac{2}{3})^{-2}$ $x = -2$ |
#3
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$2^x=A$ $3^x=B$ $4A^2 - AB - 18B^2 = 0$ ᡵÑÇ»ÃСͺ |
#4
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