\(100< 5^{2x-1}< 5^6\Rightarrow125\le5^{2x-1}\le3^5\Leftrightarrow5^3\le5^{2x-1}\le5^3\)

\(\Leftrightarrow3\le2x-1\le5\Leftrightarrow4\le2x\le6\Leftrightarrow2\le x\le3\text{ nên: x=3 hoặc x=2}\)

100 < 5^{2x - 1} ≤ 5⁶

<=> 5² . 4 < 5^{2x - 1} ≤ 5⁶

<=> 5^{2x - 1} \(\in\) { 5³; 5⁴; 5⁵; 5⁶ }

<=> 2x - 1 \(\in\) { 3; 4; 5; 6 }

<=> x \(\in\) { 2; 5/2; 3; 7/2 }

Vậy x \(\in\) {2; 5/2; 3; 7/2 }

mik ko bít

/s/:book,clock,desk,street,student,booksheft,lamp.

/z/:door,window,broad,bag,pencil,school,classroom,ruler,eraser,house,pen,teacher,chair,doctor,engineer,nurse,table,stool,telephone,

stereo.

/iz/:couch,bench.

Mk nghĩ z.Sai thui nha!Nếu đúng k mk nhé!

A = 11 . 201 = 11. ( 200 + 1 ) = 200 . 11 + 11

B = 200. 200 = 200. ( 11 + 198 ) = 200 . 11 + 200. 189

Có 200 . 11 = 200 . 11

Mà 200 . 189 > 11

=> 200 . 11 + 200. 189 > 200.11 + 11

=> B > A

Vậy B > A

thanks nha

2^x + 2^{x + 4} = 272

=> 2^x + 2^x . 2⁴ = 272

=> 2^x .( 1 + 2⁴ ) = 272

=> 2^x . 17 = 272

=> 2^x = 272 : 17 = 16

=> 2^x = 2⁴

=> x = 4

Vậy x = 4

tách số thứ 2 thành 2 ^ x . 2^ 4 có chung nhe làm bình thường nha

A = { 0;1;2;3}

B là tập hợp rỗng 

C = { 3}

D={ n e N / n < 5 }

1,\(A=\)\(1+2+2^2+2^3+...+2^{2015}\)

\(\Rightarrow2A=2+2^2+2^3+2^4+...+2^{2016}\)

\(\Rightarrow2A-A=\left(2+2^2+2^3+2^4+...+2^{2016}\right)-\left(1+2+2^2+2^3+...+2^{2015}\right)\)

    \(A=\)\(2^{2016}-1\)

                      ~~~Hok tốt~~~

2,\(B=3^{11}+3^{12}+3^{13}+...+3^{101}\)

\(\Rightarrow3B=3^{12}+3^{13}+3^{14}+...+3^{102}\)

\(\Rightarrow3B-B=\left(3^{12}+3^{13}+3^{14}+...+3^{102}\right)-\left(3^{11}+3^{12}+3^{13}+...+3^{101}\right)\)

\(\Rightarrow2B=3^{102}-3^{11}\)

\(\Rightarrow B=\frac{3^{102}-3^{11}}{2}\)

                         ~~~Hok tốt~~~