Question

Tìm số hữu tỉ x:

a) /x+\(\dfrac{1}{3}\)/-4=-1

b) 1\(\dfrac{3}{4}.x+1\dfrac{1}{2}=-\dfrac{4}{5}\)

Answer 1

\(\left|x+\dfrac{1}{3}\right|-4=-1\)

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

\(\Rightarrow\left[{}\begin{matrix}x+\dfrac{1}{3}=3\\x+\dfrac{1}{3}=-3\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{8}{3}\\x=-\dfrac{10}{3}\end{matrix}\right.\)

Answer 2

a. \(\left|x+\dfrac{1}{3}\right|-4=-1\)

\(\Rightarrow\left|x+\dfrac{1}{3}\right|=-1+4=3\)

\(\Rightarrow\left[{}\begin{matrix}x+\dfrac{1}{3}=3\\x+\dfrac{1}{3}=-3\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=\dfrac{8}{3}\\x=\dfrac{-10}{3}\end{matrix}\right.\)

Vậy..........

b. \(1\dfrac{3}{4}.x+1\dfrac{1}{2}=-\dfrac{4}{5}\)

\(\Rightarrow1\dfrac{3}{4}x=-\dfrac{4}{5}-1\dfrac{1}{2}=\dfrac{-23}{10}\)

\(\Rightarrow x=\dfrac{-23}{10}:1\dfrac{3}{4}\)

\(\Rightarrow x=\dfrac{-46}{35}\)