Question

Tìm x:

a) \(\frac{x+1}{3}=\frac{2}{7}+\frac{1}{-3}\)

b) \(\frac{x}{2}=\frac{10}{x+1}\) (x thuộc Z)

 

 

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Answer 1

\(\frac{x+1}{3}=\frac{2}{7}+\frac{1}{-3}\Leftrightarrow\frac{x+1}{3}=\frac{-6}{-21}+\frac{7}{-21}=\frac{1}{-21}\)

\(\Rightarrow\frac{x+1}{3}=\frac{1}{-21}\Leftrightarrow\left(x+1\right).21=3.1\Rightarrow x+1=\frac{3}{21}\Rightarrow x=\frac{3}{21}-1=\frac{-18}{21}=\frac{-6}{7}\)

\(\frac{x}{2}=\frac{10}{x+1}\Leftrightarrow x.\left(x+1\right)=2.10=20\Leftrightarrow4.\left(4+1\right)=20\Rightarrow x=4\)

Answer 2

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