Ta có: \(\frac{2n}{64}=26\)

           \(\frac{n}{32}=26\)

           \(n=26.32\)

           \(n=832\)

\(2^n-64=26\Rightarrow2^n=90\Rightarrow n=log_290\notinℕ\)Đề lag r

sai đề

Bài làm :

\(2^n-64=26\)

\(\Rightarrow2^n=26+64\)

\(\Rightarrow2^n=90\)

Sai đề bạn ơi

Học tốt

chào tiên

2ⁿ=16=>2ⁿ=2⁴=>n=4

\(4^{2n+1}=64\Rightarrow4^{2n+1}=4^3\)

\(\Rightarrow2n+1=4\Rightarrow n=\frac{3}{2}\)

c)\(6^n=6\Rightarrow n=1\)

k cho mk nha

a) 2ⁿ = 16

<=> 2ⁿ = 2⁴

<=> n = 4

b) 2²ⁿ⁺¹ = 64

<=> 2²ⁿ⁺¹ = 2⁶

<=> 2n+1 = 6

2n = 6 - 1

2n = 5

n = 5 :2

n = \(\frac{5}{2}\)

c) 6ⁿ . 243 = 1458

6ⁿ = 1485 : 243

6ⁿ = \(\frac{55}{9}\)

=> n vô hợp lý

Bài 1 :

\(A=\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}\)

\(\dfrac{1}{2}xA=\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}+\dfrac{1}{128}\)

\(A-\dfrac{1}{2}xA=\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}-\left(\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}+\dfrac{1}{128}\right)\)

\(\dfrac{1}{2}xA=\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}-\dfrac{1}{4}-\dfrac{1}{8}-\dfrac{1}{16}-\dfrac{1}{32}-\dfrac{1}{64}-\dfrac{1}{128}\)

\(\dfrac{1}{2}xA=\dfrac{1}{2}-\dfrac{1}{128}\)

\(\dfrac{1}{2}xA=\dfrac{64}{128}-\dfrac{1}{128}\)

\(\dfrac{1}{2}xA=\dfrac{63}{128}\)

\(A=\dfrac{63}{128}:\dfrac{1}{2}=\dfrac{63}{128}x\dfrac{2}{1}=\dfrac{63}{64}\)

Bài 2 :

Số tự nhiên có 2 chữ số là \(\overline{ab}\left(a;b\inℕ\right)\)

Thêm số 12 vào bên trái số đó :

\(\overline{12ab}=26x\overline{ab}\)

\(1200+10xa+b=26x\left(10xa+b\right)\)

\(1200+10xa+b=260xa+26xb\)

\(260xa-10xa+26xb-b=1200\)

\(250xa+25xb=1200\)

\(25x\left(10xa+b\right)=1200\)

\(10xa+b=48\)

\(\Rightarrow\left\{{}\begin{matrix}a=4\\b=8\end{matrix}\right.\)

Vậy số đó là \(48\)

gấp ạ . 4h em học rồi 

Tả lời là em tick luôn cho

a) \(2n+7⋮2n+1\)

\(\Rightarrow\left(2n+1\right)+6⋮2n+1\)

\(\Rightarrow6⋮2n+1\)(vì \(2n+1⋮2n+1\))

\(\Rightarrow2n+1\inƯ\left(6\right)\)

\(\Rightarrow2n+1\in\left\{1;2;3;6\right\}\)

\(\Rightarrow\)\(2n\in\left\{0;1;2;5\right\}\)

\(\Rightarrow n\in\left\{0;1\right\}\)

b) \(3m-9⋮3m-1\)

\(\Rightarrow\left(3m-1\right)-8⋮3m-1\)

\(\Rightarrow8⋮3m-1\)(vì \(3m-1⋮3m-1\))

\(\Rightarrow3m-1\inƯ\left(8\right)\)

\(\Rightarrow3m-1\in\left\{1;2;4;8\right\}\)

\(\Rightarrow3m\in\left\{2;3;5;9\right\}\)

\(\Rightarrow m\in\left\{1;3\right\}\)

Hok "tuốt" nha^^

goi 3 so la a;b;c  theo de bai ta co  a+b=56    ;    b+c=64     ;     c+a=78

=> a+b+b+c+c+a=56+64+78=198      => a+b+c=99  (*)

thay a+b=56  vao * ta duoc   c=99-56=43

thay b+c=64   vao * ta duoc  a=99-64=35

thay c+a=78  vao * ta duoc    b=99-78=21

vay 3 so la 43;34;21

h dung nha

Số lớn là 406

Số bé là 422

Phan Ha Giang sai S.l ma nho hon so be

hieu cua so lon va so be la: 15*1+1=16

so be la: (828-16) / 2 = 406

so lon la: 828-406= 422