2 ^{2x + 1} - 9.2 ^{x} + 4 = 0 pleas I need this answer. I want to submit it now.​

Question

2 ^{2x + 1} - 9.2 ^{x} + 4 = 0
pleas I need this answer. I want to submit it now.​

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Thành Công 4 years 2021-07-26T00:36:18+00:00 1 Answers 6 views 0

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  1. dangkhoa
    0
    2021-07-26T00:37:22+00:00
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    \displaystyle\bf 2^{2x+1}-9\cdot 2^x+4=0 \quad ; \qquad \boxed{ 2^x=t \; ; \; 2^{2x}=t^2} \\\\2t^2-9t+4=0 \\\\D=81-32 =49 \\\\ t_1=\frac{9+7}{4} =4 \\\\ t_2=\frac{9-7}{4} =\frac{1}{2} \\\\1) \ 2^x=4 \Longrightarrow x_1=2 \qquad 2) \ 2^x=2^{-1}\Longrightarrow x_2=-1 \\\\Answer: \boxed{x_1=2 \quad ; \quad x_2=-1}

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )