a) 2^x.2^4=128

=>2^x.2^2=2^7

=>2^x=2^7:2^2

=>2^x=2^5

=>x=5

b)x^15=x

=>x^15-x=0

=>x(x^16-x)=0

=>2 trượng hợp:x=0 và x^16-1=0(x^16-1=0 cx 2 th nha)

b),d),e) như nhau nha!

c) dễ rồi

\(a)2^x\cdot4=128\)

\(\Rightarrow2^x=\frac{128}{4}\)

\(\Rightarrow2^x=32\)

\(\Rightarrow2^x=2^5\)

\(\Rightarrow x=5\)

\(b)x^{15}=x\)

\(\Rightarrow x^{15}-x=0\)

\(\Rightarrow x(x^{14}-1)=0\)

\(\Rightarrow\hept{\begin{cases}x=0\\x^{14}-1=0\end{cases}}\)\(\Rightarrow\hept{\begin{cases}x=0\\x^{14}=1\end{cases}\Rightarrow}\hept{\begin{cases}x=0\\x=1\end{cases}}\)

\(c)(2x+1)^3=125\)

\(\Rightarrow(2x+1)^3=5^3\)

\(\Rightarrow2x+1=5\)

\(\Rightarrow2x=5-1\)

\(\Rightarrow2x=4\)

\(\Rightarrow x=4:2=2\)

\(d)(x-5)^4=(x-5)^6\)

\(\Rightarrow(x-5)^6-(x-5)^4=0\)

\(\Rightarrow(x-5)^4\cdot\left[(x-5)^2-1\right]=0\)

\(\Rightarrow\orbr{\begin{cases}(x-5)^4=0\\(x-5)^2-1=0\end{cases}\Rightarrow}\orbr{\begin{cases}x=0\\x=6\end{cases}}\)

\(e)(2x-15)^5=(2x-15)^3\)

\(\Rightarrow(2x-15)^5-(2x-15)^3=0\)

\(\Rightarrow(2x-15)^3-\left[(2x-15)^2-1\right]=0\)

\(\Rightarrow\orbr{\begin{cases}(2x-15)^3=0\\(2x-15)^2-1=0\end{cases}\Rightarrow}\orbr{\begin{cases}x=\varnothing\\x=8\end{cases}}\)

Chúc bạn hoc tốt :>

diều kiện xác định là các mẫu phải khác o; số chia cũng khác o nhé:

ĐK: +)  \(x+5\ne0\Rightarrow x\ne-5\)

+)  \(2x-15\ne0\Rightarrow x\ne\frac{15}{2}\)

+)  \(x^2-25\ne0\Rightarrow\left(x+5\right)\left(x-5\right)\ne0\Rightarrow x\ne\pm5\)

+)  \(1-x\ne0\Rightarrow x\ne1\)

Vậy điều kiện xác đinh của A là : \(x\ne1;x\ne\frac{15}{2};x\ne\pm5\)

a,x=2

b,x=5

x=4

x=6

a) \(\left(2x+1\right)^3=125\)

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

\(\Rightarrow2x+1=5\)

\(\Rightarrow2x=5-1\)

\(\Rightarrow2x=4\)

\(\Rightarrow x=4:2\)

\(\Rightarrow x=2\)

Vậy x = 2

b) \(\left(x-5\right)^4=\left(x-5\right)^6\)

\(\Rightarrow\left(x-5\right)^4-\left(x-5\right)^6=0\)

\(\Rightarrow\left(x-5\right)^4\left[1-\left(x-5\right)^2\right]=0\)

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

TH 1 : \(\left(x-5\right)^4=0\Rightarrow x-5=0\Rightarrow x=5\)

TH 2 : \(\left(x-5\right)^2=1\Rightarrow\orbr{\begin{cases}x-5=1\\x-5=-1\end{cases}}\Rightarrow\orbr{\begin{cases}x=6\\x=4\end{cases}}\)

Vậy  \(x\in\left\{5;6;4\right\}\)

c) \(\left(2x-15\right)^5=\left(2x-15\right)^3\)

\(\Rightarrow\left(2x-15\right)^5-\left(2x-15\right)^3=0\)

\(\Rightarrow\left(2x-15\right)^3\left[\left(2x-15\right)^2-1\right]=0\)

\(\Rightarrow\orbr{\begin{cases}\left(2x-15\right)^3=0\\\left(2x-15\right)^2-1=0\end{cases}}\Rightarrow\orbr{\begin{cases}\left(2x-15\right)^3=0\\\left(2x-15\right)^2=1\end{cases}}\)

TH 1 : \(\left(2x-15\right)^3=0\Rightarrow2x-15=0\Rightarrow2x=15\Rightarrow x=\frac{15}{2}\)

TH 2 : \(\left(2x-15\right)^2=1\Rightarrow\orbr{\begin{cases}2x-15=1\\2x-15=-1\end{cases}}\Rightarrow\orbr{\begin{cases}2x=16\\2x=14\end{cases}}\Rightarrow\orbr{\begin{cases}x=8\\x=7\end{cases}}\)

Vậy  \(x\in\left\{\frac{15}{2};8;7\right\}\)

_Chúc bạn học tốt_

Bài giải:

a) 3x (12x - 4) - 9x (4x - 3) = 30

36x² – 12x – 36x² + 27x = 30

15x = 30

Vậy x = 2.

b) x (5 - 2x) + 2x (x - 1) = 15

5x – 2x² + 2x² – 2x = 15

3x = 15

x =5

a) 3x (12x - 4) - 9x (4x - 3) = 30

36x² – 12x – 36x² + 27x = 30

15x = 30

Vậy x = 2.

b) x (5 - 2x) + 2x (x - 1) = 15

5x – 2x² + 2x² – 2x = 15

3x = 15

x =5

a./ \(\Leftrightarrow x^{10}=1\Leftrightarrow x=\pm1\)

b./ \(\Leftrightarrow x^{10}-x=0\Leftrightarrow x\left(x^9-1\right)=0\Leftrightarrow\orbr{\begin{cases}x=0\\x^9=1\end{cases}\Leftrightarrow\orbr{\begin{cases}x=0\\x=1\end{cases}}}\)

c./ \(\Leftrightarrow\left(2x-15\right)^5-\left(2x-15\right)^3=0\Leftrightarrow\left(2x-15\right)^3\left(\left(2x-15\right)^2-1\right)=0\Leftrightarrow\orbr{\begin{cases}2x-15=0\\\left(2x-15\right)^2=1\end{cases}}\)

• 2x - 15 = 0 \(\Leftrightarrow x=\frac{15}{2}\)
• 2x - 15 = 1 \(\Leftrightarrow x=\frac{16}{2}=8\)
• 2x - 15 = -1 \(\Leftrightarrow x=\frac{14}{2}=7\)

1^10=1^1

1^10=1

(2*8-15)^3=(2*8)^3

Ý c,x có thể bằng 7

a) \(\left(2x-1\right)\left(2x+1\right)-4x^2=3\Leftrightarrow\left(4x^2-1\right)-4x^2=3\Rightarrow-1=3\) (không đúng)

Tí làm tiếp nhé ;) h đi chơi đã

Ta có:

\(a)\left(2x-5\right)\left(x+2\right)-2x\left(x-1\right)=15\)

\(\Leftrightarrow\left(2x^2-x-10\right)-\left(2x^2-2x\right)=15\Leftrightarrow x-10=15\)

\(\Leftrightarrow x=25\)

\(b)\left(5-2x\right)\left(2x+7\right)=4x^2-25\)

\(\Leftrightarrow\left(5-2x\right)\left(2x+7\right)=\left(2x-5\right)\left(2x+5\right)\)

\(\Leftrightarrow\left(5-2x\right)\left(4x+12\right)=0\)

\(5-2x=0\Leftrightarrow x=\frac{5}{2}\)

\(4x+12=0\Leftrightarrow x=-3\)

Vậy ..........................................

\(\left(2x-15\right)^3=\left(2x-15\right)^5\\ \Rightarrow\left(2x-15\right)^2=1\\ \Rightarrow\left[{}\begin{matrix}2x-15=-1\\2x-15=1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=7\\x=8\end{matrix}\right.\)

giúp mik ik mik tic cho và nhớ cho thêm cả hướng dẫn