\(a,2^x.4=128\\2^x.2^2=2^7\\ 2^x=\dfrac{2^7}{2^2}=2^{7-2}=2^5\\ Vậy:x=5\\ ----\\ b,\left(2x+1\right)^3=125=5^3\\ \Rightarrow 2x+1=5\\ 2x=5-1=4\\ x=\dfrac{4}{2}=2\\ ----\\ c,2x-2^6=6\\ 2x=6+2^6=6+64\\ 2x=70\\ x=\dfrac{70}{2}=35\\ ----\\ d,49.7^x=2401\\ 7^x=\dfrac{2401}{49}=49=7^2\\ Vậy:x=2\)

3:

a: 3^x*3=243

=>3^x=81

=>x=4

b; 2^x*16^2=1024

=>2^x=4

=>x=2

c: 64*4^x=16^8

=>4^x=4^16/4^3=4^13

=>x=13

d: 2^x=16

=>2^x=2^4

=>x=4

`@` `\text {Ans}`

`\downarrow`

`2^x * 4 = 128`

`=> 2^x = 128 * 4`

`=> 2^x = 512`

`=> 2^x = 2^9`

`=> x = 9`

Vậy, `x = 9`

`x^15 = x`

`=> x^15 - x = 0`

`=> x(x^14 - 1) = 0`

`=>` TH1: `x = 0`

`TH2: x^14 - 1 = 0`

`=> x^14 = 1`

`=> x = 1`

Vậy, `x \in {0; 1}`

`(2x+1)^3 = 125`

`=> (2x+1)^3 = 5^3`

`=> 2x + 1 = 5`

`=> 2x = 5 - 1`

`=> 2x =4`

`=> x = 4 \div 2`

`=> x = 2`

Vậy,` x = 2.`

`(x - 5)^4 = (x-5)^6`

`=> (x-5)^4 - (x-5)^6 = 0`

`=> (x-5)^4 * [ 1 - (x-5)^2] = 0`

`=> - (x-6)(x-5)^4(x-4) = 0`

`TH1: (x - 5)^4 = 0`

`=> x - 5 = 0`

`=> x = 0 +5`

`=> x = 5`

`TH2: x - 6=0`

`=> x=6`

`TH3: x-4=0`

`=> x = 4`

Vậy, `x \in {4; 5; 6}`

a: =>2^x=32

=>x=5

b: =>x^15-x=0

=>x(x^14-1)=0

=>x=0; x=1;x=-1

c: =>2x+1=5

=>2x=4

=>x=2

d: =>(x-5)^4[(x-5)^2-1]=0

=>(x-5)(x-4)(x-6)=0

=>x=5;x=4;x=6

`\color{grey}\text{#071931}`

`(4 + 2x) * (9 - 3x) = 0`

TH1: `4 + 2x = 0 => 2x = -4 => x = -2`

TH2: `9 - 3x = 0 => 3x = 9 => x = 3`

Vậy, `x \in {-2; 3}`

____

`(3x - 19)^3 = 125`

`=> (3x - 19)^3 = 5^3`

`=> 3x - 19 = 5`

`=> 3x = 24`

`=> x = 8`

Vậy, `x = 8.`

a) \(\left(2x-1\right)^4=16\)

\(\)TH1: \(\left(2x-1\right)^4=2^4\)

\(=>2x-1=2\)

\(2x=2+1\)

\(2x=3\)

\(x=\dfrac{3}{2}\)

TH2: \(\left(2x-1\right)^4=\left(-2\right)^4\)

\(=>2x-1=-2\)

\(2x=-2+1\)

\(2x=-1\)

\(x=\dfrac{-1}{2}\)

Vậy x = \(\dfrac{3}{2}\) hoặc x = \(\dfrac{-1}{2}\)

________--

b) \(\left(2x+1\right)^3=125\) ( mình nghĩ đề bài đúng là vầy )

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

\(=>2x+1=5\)

\(2x=5-1\)

\(2x=4\)

\(x=4:2\)

\(x=2\)

Vậy x = \(2\)

a)125 : x = 2² - (-1)

125 : x = 4 + 1

125 : x = 5

x = 125 : 5

x = 25

-------------------------------------------------

b) 2x - 8 = -4

2x = (-4) + 8

2x = 4

x = 4 : 2 

x = 2

-----------------------------------------------------------

c) Xem lại đề.

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

\(=>125:x=4+1\)

\(=>125:x=5\)

\(=>x=125:5\)

\(=>x=25\)

_____

\(2x-8=-4\)

\(=>2x=\left(-4\right)+8\)

\(=>2x=4\)

\(=>x=4:2\)

\(=>x=2\)

_______

\(6^{2x+5}=216\)

\(=>6^{2x+5}=6^3\)

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

\(=>2x=3-5\)

\(=>2x=-2\)

\(=>x=\left(-2\right):2\)

\(=>x=-1\)

\(#NqHahh\)

125:x=2² - (-1)

125:x=4+1

125:x=5

X=125:5

X=25

2x -8 = -4

2x=-4+8

2x=4

X=4:2

X=2

6²(x+5)  = 216

36(x+5) = 216

X+5 = 216:36

X+5=6

X=6-5

X=1

a. 7/12 - 1/4 : ( -4/11 - x ) = 125%

=> 1/4 : ( -4/11 - x ) = 7/12 - 5/4 = -2/3

=> -4/11 - x = 1/4 : -2/3 

=> -4/11 - x = -3/8

=> x = -4/11 - ( -3/8 )

=> x = 1/88

b. 1/2x - 1/3 = 2/3x - 5/6

=> 1/2x - 2/3x = 1/3 - 5/6

=> -1/6x = -1/2

=> x = -1/2 : -1/6

=> x = 3

a) \(x^3+15x^2+75x=-125\)

\(\Leftrightarrow x^3+15x^2+75x+125=0\)

\(\Leftrightarrow x^3+125+15x^2+75x=0\)

\(\Leftrightarrow\left(x+5\right)\left(x^2+5x+25\right)+15x\left(x+5\right)=0\)

\(\Leftrightarrow\left(x+5\right)\left(x^2+20x+25\right)=0\)

\(TH1:x+5=0\Leftrightarrow x=-5\)

\(TH2:x^2+20x+25=0\)

\(\Leftrightarrow\left(x+10\right)^2=75\)

\(\Leftrightarrow\orbr{\begin{cases}x=\sqrt{75}-10\\x=-\sqrt{75}-10\end{cases}}\)

b) \(x\left(x-3\right)\left(x+3\right)-\left(x+2\right)\left(x^2-2x+4\right)=10\)

\(\Leftrightarrow x\left(x^2-9\right)-\left(x^3+8\right)=10\)

\(\Leftrightarrow x^3-9x-x^3-8=9\)

\(\Leftrightarrow-9x=17\)

\(\Leftrightarrow x=\frac{-17}{9}\)

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.