Trả lời:

a, \(3\left|x\right|+2=5\)

\(\Leftrightarrow3\left|x\right|=3\)

\(\Leftrightarrow\left|x\right|=1\)

\(\Leftrightarrow\orbr{\begin{cases}x=1\\x=-1\end{cases}}\)

Vậy x = 1; x = - 1

b, \(4-\left|x\right|=\frac{1}{4}\)

\(\Leftrightarrow\left|x\right|=\frac{15}{4}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{15}{4}\\x=-\frac{15}{4}\end{cases}}\)

Vậy x = 15/4; x = - 15/4

c, \(4+\left|2x\right|=\frac{2}{3}\)

\(\Leftrightarrow\left|2x\right|=\frac{10}{3}\)

\(\Leftrightarrow\orbr{\begin{cases}2x=\frac{10}{3}\\2x=-\frac{10}{3}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{5}{3}\\x=-\frac{5}{3}\end{cases}}}\)

Vậy x = 5/3; x = - 5/3

d, \(3\left|x\right|=\frac{1}{7}-\frac{1}{8}\)

\(\Leftrightarrow3\left|x\right|=\frac{1}{56}\)

\(\Leftrightarrow\left|x\right|=\frac{1}{168}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{168}\\x=-\frac{1}{168}\end{cases}}\)

Vậy x = 1/168; x = - 1/168

a, \(|-2,1|\)\(=2,1\)

b,\(|-\)\(\frac{2}{9}|\)\(=\frac{2}{9}\)

c,\(|12,2|\)\(=12,2\)

d,\(|0|\)\(=0\)

e,\(|\frac{3}{2}|\)=\(\frac{3}{2}\)

Hok tốt~

\(\frac{3}{11}:-\frac{9}{5}+\frac{3}{11}:-\frac{18}{13}\)

\(=\frac{3}{11}\cdot-\frac{5}{9}+\frac{3}{11}\cdot-\frac{13}{18}\)

\(=\frac{3}{11}\cdot\left(-\frac{5}{9}+-\frac{13}{18}\right)\)

\(=\frac{3}{11}\cdot-\frac{23}{18}\)

\(=-\frac{23}{66}\)

- \(\frac{13}{66}\)

\(\frac{2x-5}{y+1}=\frac{x-1}{3y}=\frac{1}{3}\Rightarrow\hept{\begin{cases}3\left(2x-5\right)=y+1\\x-1=y\end{cases}}\)

\(\Rightarrow6x-15=x-1+1\)

\(\Leftrightarrow x=3\)

suy ra \(y=2\). 

đề bài sai nha

BC=BC

suy ra ABC=ADC

vì ABC DÀI  BẰNG ADC