\(\frac{2}{3}x-\frac{3}{12}=\frac{4}{5}-\left(\frac{7}{x-2}\right)\)

\(\Rightarrow\frac{2}{3}x+\frac{7}{x-2}=\frac{4}{5}+\frac{3}{12}\)

\(\Rightarrow\frac{2x+17}{3\left(x-2\right)}=\frac{21}{20}\)

\(\Rightarrow20\left(2x+17\right)=21.3\left(x-2\right)\)

\(\Rightarrow40x+340=63x-126\)

\(\Rightarrow63x-40x=126+340\)

\(\Rightarrow13x=466\)

\(\Rightarrow x=\frac{466}{13}\)

TL:

200 x 79 = 15800.

~HT~

200x79=15 800 xin k

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x/y=2/3 => x/2= y/3

Đặt x/2=y/3=k ( k thuộc Z)

=> X=2K

     Y=3K

VÌ X.Y= 54

<=> 2K.3K=54

        K MŨ 2 .6=54

K MŨ 2 BẰNG 9

XÉT 2 TH 

* K=3

=> X=2K=2.3=6; Y=3K=3.3=9

*K=-3

=> X= 2K=2.(-3)= -6;Y= 3.(-3)=-9

VẬY CÁC CẶP (X;Y) CẦN TÌM LÀ : ( 6;9); -6;-9)

\(\left|x\right|+x=\frac{1}{3}\)

\(\Rightarrow\left|x\right|=\frac{1}{3}-x\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{1}{3}-x\\x=\frac{-1}{3}+x\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}2x=\frac{1}{3}\\0=\frac{-1}{3}\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{1}{6}\\x=\varnothing\left(ktm\right)\end{cases}}\)

Vậy \(x=\frac{1}{6}\)

Đáp án là A>B!

Học tốt!

A>B

vì A>B