\(A=3^x+3^{x+1}+...+3^{x+100}\)

=>\(3A=3^{x+1}+3^{x+2}+...+3^{x+101}\)

=>\(2A=3^{x+101}-3^x\)

=>\(A=\dfrac{3^{x+101}-3^x}{2}\)

=>\(3^{x+101}-3^x=3^{105}-3^4\)

=>x=4

x=4

Tim x sao cho 3x+2 chia het cho x-1?

Ta co: 3x+2=3.(x-1)+5 
Vi 3.(x-1) chia het cho x-1 
=>De 3x+2 chia het cho x-1 thi 5 chia het cho x-1 
=>x-1 thuoc uoc cua 5 
=>x-1 thuoc tap hop -1;1;5;-5 
=>x thuoc tap hop 0;2;6;-4

(x+1)^3=-343

(x+1)^3=(-7)x(-7)x(-7)

  x+`1  =-7

  x       =(-7)-1

  x       =-8

la -8 do.pn pick mk nhe

(x + 1)³ = -343 = (-7)³

x + 1 = -7

x = -7 - 1

x=  -8 

Vậy x = -8

( x + 1 )^3=-343

x + 1 = -7

x = -7 - 1 = -8

(x+1)^3=(-7)^3

<=>x+1=-7

<=>x=-7 - 1

<=>x=-8

tick mk nha

(x+1)³= -343

=> x+1= -7

=> x = -8

tk mình nha

thank quá nhìu

tk đấy nhớ nha nha nha nha nha

giúp tôi nha

( 3. x + 1 )³ = 343

( 3. x + 1 )³ = 7³

=> 3x + 1 = 7

=> 3x = 6

=> x = 2

 ( x +1) ³ = -343  = ( -7)³

=> x +1 = -7

=> x = -8

a ) ( x - 1 )³ = 343

7³ = 343

x + 1 = 7

x = 7 - 1

x = 6

b ) ( x - 2 )⁴ = 4096

8⁴ = 4096

x - 2 = 8

x = 8 + 2

x = 10

\(\left(x-1\right)^3=343=7^3\) => x -1 =7 => x =8

\(\left(x-2\right)^4=4096=8^4=\left(-8\right)^4\)\(\Rightarrow\orbr{\begin{cases}x-2=8\\x-2=-8\end{cases}\Rightarrow\orbr{\begin{cases}x=10\\x=-6\end{cases}}}\)

a) \(\left(x-1\right)^3=343\)

\(\left(x-1\right)=7^3\)

  \(x-1=7\)

  \(x=7+1\)        

  \(x=8\)

b) \(\left(x-2\right)^4=4094\)

    \(\left(x-2\right)^4=8^4\)

      \(x-2=8\) hoặc \(x-2=-8\)

      \(x=8+2\)         \(x=-8+2\)

      \(x=10\)               \(x=-6\)

Vậy \(x=10\) hoặc \(x=-6\)