a) Ta có:  ( 2 x + 1 ) 3 = 3 3 nên 2x + 1 = 3. Do đó x = 1.

b) Ta có: ( 2 x - 1 ) 3 = 5 3 nên 2x - 1 = 5. Do đó x = 3.

a) x = 2 

b) x = 2     

c) x = 2

d) x = 1.

(2x-1)\(^3\)=-125

(2x-1)\(^3\)= - 5\(^3\)

2x - 1 = -5

2x = -5+1

2x =-4

x = -4:2

x = -2

Nếu bài dễ thì cố gắng tự làm bạn nhé.

Bài 1:

a) \(2x+3=5\)

\(\Leftrightarrow2x=5-3=2\)

\(\Leftrightarrow x=2:2=1\)

Vậy: x=1

b) \(\left(2x-3\right)^2=9\)\(=3^2=\left(-3\right)^2\)

\(\Rightarrow\left[{}\begin{matrix}2x-3=3\\2x-3=-3\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\left(3+3\right):2=3\\x=\left(-3+3\right):2=0\end{matrix}\right.\)

Vậy: \(x\in\left\{3;0\right\}\)

c) \(3x+4=2x-7\)

\(\Leftrightarrow2x-3x=7+4\)

\(\Leftrightarrow-1x=11\)

\(\Leftrightarrow x=-11\)

Vậy: x=-11

d) \(\left(4x-1\right)^3=27\)\(=3^3\)

\(\Rightarrow4x-1=3\)

\(\Leftrightarrow4x=3+1=4\)

\(\Leftrightarrow x=4:4=1\)

Vậy: x=1

e) \(\left(x-7\right).2=3.\left(2x+4\right)\)

\(\Leftrightarrow2x-14=6x+12\)

\(\Leftrightarrow2x-6x=12+14\)

\(\Leftrightarrow-4x=26\)

\(\Leftrightarrow x=\frac{26}{-4}=\frac{13}{-2}\)

Vậy: \(x=\frac{13}{-2}\)

a) 2^x . 4 = 128

<=> 2^x = 32 

<=> 2^x = 2⁵

<=> x = 5

b) x¹⁵ = x¹

<=> x¹⁵ - x = 0

<=> x(x¹⁴ - 1) = 0

<=> \(\orbr{\begin{cases}x=0\\x^{14}-1=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=0\\x^{14}=1^{14}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=0\\x=\pm1\end{cases}}\)

c) (2x + 1)³ = 125

<=> (2x + 1)³ = 5³

<=> 2x + 1 = 5

<=> 2x = 4

<=> x = 2

d) (x - 5)⁴ = (x - 5)⁶

<=> (x - 5)⁶ - (x - 5)⁴ = 0

<=> (x - 5)⁴[(x - 5)² - 1] = 0

<=> \(\orbr{\begin{cases}\left(x-5\right)^4=0\\\left(x-5\right)^2-1=0\end{cases}}\)

Khi (x - 5)⁴ = 0 => x - 5 = 0 => x = 5

Khi (x - 5)² - 1 = 0 <=> (x - 5)² = 1² <=> \(\orbr{\begin{cases}x-5=1\\x-5=-1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=6\\x=4\end{cases}}\)

a, 2x . 4 = 128

=> 2x = 128 : 4 = 32

=> x = 32 : 2 = 16

Vậy x = 16

b, x15 = x 1 => Sai đề

c, (2x + 1)³ = 125

=> ( 2x + 1 ) = 5³

=> 2x + 1 = 5 

=> 2x = 5 - 1

=> 2x = 4

=> x = 4 : 2

=> x = 2

a) 3⁵= 243

b)5³=125

tiếp theo bn tự tính nhé

a) \(\left(2x-1\right)^5=243\)

\(\left(2x-1\right)^5=3^5\)

\(\Rightarrow2x-1=3\)

\(2x=3+1\)

\(2x=4\)

\(x=\frac{4}{2}\)

\(x=2\)

Vậy .......

b) \(\left(3x+2\right)^3=125\)

\(\left(3x+2\right)^3=5^3\)

\(\Rightarrow3x+2=5\)

\(3x=5-2\)

\(3x=3\)

\(x=\frac{3}{3}=1\)

Vậy ..........

\(\left(2x-1\right)^3=125\)

\(\Leftrightarrow\left(2x-1\right)^3=5^3\)

\(\Leftrightarrow2x-1=5\Leftrightarrow x=3\)

             \(------\)

\(\left(2x-1\right)^5=x^5\)

\(\Leftrightarrow2x-1=x\)

\(\Leftrightarrow x=1\)