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1 . 2x+21-x=3

A. $(1, 2)$
B. $(0, 2)$
C. $(1, 3)$
D. $(0, 1)$

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Answer: Option D

Explanation:

৩৮ তম বিসিএস প্রিলিমিনারি টেস্ট (29-12-2017)

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2 . 2x+21-x=3

A. (1,2)
B. (0,2)
C. (1,3)
D. (0,1)

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Answer: Option D

Explanation:

2^{x} + 2^{1 - x} = 3 \Rightarrow 2^{x} + \frac{2^{1}}{2^{x}} = 3 \Rightarrow a + \frac{2}{a} = 3 [2^{x} = a] \Rightarrow a^{2} + 2 = 3 a \Rightarrow a^{2} - 3 a + 2 = 0 \Rightarrow a^{2} - 2 a - a + 2 = 0 \Rightarrow a (a - 2) - 1 (a - 2) = 0 \Rightarrow (a - 1) (a - 2) = 0 এখন, a-2=0                             আবার, a-1=0 a = 2 a = 1 \Rightarrow 2^{x} = 2^{1} \Rightarrow 2^{x} = 2^{0} \Rightarrow x = 1 \Rightarrow x = 0 ∴ x = 1, 0

রেলপথ মন্ত্রণালয় ।। কম্পিউটার অপারেটর (12-06-2021)

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