đây nhé

ghi loi giai giup minh nha

\(\frac{2}{3}=\frac{6}{9}\)

\(\frac{3}{2}=\frac{9}{6}\)

(2x - 1)⁶ = (2x - 1)⁸ 

<=> (2x - 1)⁸ - (2x - 1)⁶ = 0 

<=> (2x - 1)⁶[(2x - 1)² - 1] = 0 

<=> \(\orbr{\begin{cases}\left(2x-1\right)^6=0\\\left(2x-1\right)^2-1=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}2x-1=0\\\left(2x-1\right)^2=1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{2}\\2x-1=\pm1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{2}\\x\in\left\{1;0\right\}\end{cases}}\)

Vậy \(x\in\left\{1;0;\frac{1}{2}\right\}\)

\(0,45=\frac{45}{100}=\frac{9}{20}\)

\(1,35=\frac{135}{100}=\frac{27}{20}\)

\(25,5:1\frac{9}{42}=\frac{255}{10}:\frac{51}{42}=\frac{51}{2}:\frac{17}{14}=\frac{51}{2}.\frac{14}{17}=7.3=21:1\)

Ta có :

\(\frac{x}{0,25}=\frac{0,003}{0,75}\)

\(\Rightarrow\frac{3x}{0,75}=\frac{0,003}{0,75}\)

=> 3x = 0,003

=> x = 0,001

x:2,5=0,003:0,75

⇒x.2/5=3/1000.4/3

⇒x.2/5=1/250

⇒x=1/100

\(\frac{2}{3}-3\left(\frac{1}{2}+\frac{3}{4}\right)\)

\(=\frac{2}{3}-3\left(\frac{2}{4}+\frac{3}{4}\right)\)

\(=\frac{2}{3}-3.\frac{5}{4}\)

\(=\frac{2}{3}-\frac{15}{4}\)

\(=-\frac{37}{12}\)

\(\frac{2}{3}-3.\left(\frac{1}{2}+\frac{3}{4}\right)=\frac{2}{3}-\frac{3}{2}-\frac{9}{4}\)

\(=\frac{8}{12}-\frac{18}{12}-\frac{27}{12}=\frac{-37}{12}\)