2.5-X=1.3 suy ra X =1.2

2-5-X=-1.3 suy ra X=3.8

de vay ma ko bít

\(\Rightarrow2,5-x=1,3\)

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

\(\Leftrightarrow\orbr{\begin{cases}2,5-x=1,3\\2,5-x=-1,3\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=2,5-1,3\\x=2,5+1,3\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=1,2\\x=3,8\end{cases}}\)

  Vậy \(x\in\){1,2 ; 3,8}

\(\left(x^4\right)^2=\frac{x^{12}}{x^5}\)

\(x^8=x^{12}:x^5\)

\(x^8=x^7\)

=> x⁸ - x⁷ = 0

x⁷.(x-1) = 0

=> x⁷ = 0=> x = 0

x-1 = 0 => x = 1

KL:  x = 1 hoặc x = 0

\(\frac{x}{\left(x^4\right)^2}=\frac{x^{12}}{x^5}\)

=>\(\frac{x}{x^8}=x^7\)

=>\(\frac{1}{x^7}=x^7\)

=>\(1=x^7.x^7\)

=>\(1^{14}=x^{14}\)

=>\(x=1\)

Bài này \(x^5\rightarrow x^4\) mới đúng chứ?

\(\frac{x^{12}}{x^4}=x^{\left(12-4\right)}=x^8=\left(x^4\right)^2\)

9 x 4-x=24

36 - x  = 24

       x  = 36 - 24

       x  =  12

Vậy x = 12

9*4 - x = 24

=> 9x4 - x = 24

=> 36 -x = 24

=> x= 36 - 24

=> x= 12

vậy x= 12

9 . 4 - x = 24

36 - x = 24

x = 36 - 24

x = 12

\(A=x+\dfrac{1}{x-2}\\ \Rightarrow A=x-2+\dfrac{1}{x-2}+2\)

Áp dụng BĐT Cô-si ta có:

\(A=x-2+\dfrac{1}{x-2}+2\\ \ge2\sqrt{\left(x-2\right).\dfrac{1}{x-2}}+2\\ =2\sqrt{1}+2\\ =4\)

 \(\text{Dấu "=" xảy ra}\Leftrightarrow x-2=\dfrac{1}{x-2}\\ \Leftrightarrow\left(x-2\right)^2=1\\ \Leftrightarrow\left[{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=3\left(tm\right)\\x=1\left(ktm\right)\end{matrix}\right.\)

Vậy \(A_{min}=4\Leftrightarrow x=3\)

\(A=x-2+\dfrac{1}{x-2}+2\ge2+2=4\)

Dấu '=' xảy ra khi x-2=1 hoặc x-2=-1

=>x=3 hoặc x=1