Giải giúp mình câu này, thankyou !

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Giải giúp mình câu này, thankyou !
giai-giup-minh-cau-nay-thankyou

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Môn Toán Euphemia 4 years 2020-11-25T07:53:57+00:00 2020-11-25T07:53:57+00:00 2 Answers 52 views 0

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

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Ladonna · Answer 1 · 2020-11-25T07:55:11+00:00

Ladonna

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2020-11-25T07:55:11+00:00 November 25, 2020 at 7:55 am

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$A = 1 + 2 + 2^{2} + \dots + 2^{50}$

$2 A = 2 + 2^{2} + 2^{3} + \dots + 2^{51}$

$2 A - A = (2 + 2^{2} + 2^{3} + \dots 2^{51}) - (1 + 2 + 2^{2} + \dots + 2^{50})$

$A = 2^{51} - 1$

$A + 1 = 2^{51} - 1 + 1 = 2^{51}$

$\to$ ĐPCM

Nem · Answer 2 · 2020-11-25T07:55:32+00:00

Nem

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2020-11-25T07:55:32+00:00 November 25, 2020 at 7:55 am

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Đáp án:

Giải thích các bước giải:

`a=1+2+2^2+2^3+….+2^50`
`=>2a=2+2^2+2^3+2^4+…+2^51`
`=>2a-a=a=2^51-1`
`=>a+1=2^51`
vậy a+1 là 1 lũy thừa