câu 3:
a) \(\left|2,5-x\right|=1,3\\ \Rightarrow\left[{}\begin{matrix}2,5-x=-1,3\\2,5-x=1,3\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=3,8\\x=1,2\end{matrix}\right.\)
b) \(\left|x-3,5\right|=7,5\\ \Rightarrow\left[{}\begin{matrix}x-3,5=-7,5\\x-3,5=7,5\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=-4\\x=11\end{matrix}\right.\)
c) \(\left|x+\dfrac{5}{4}\right|=0\\ \Rightarrow x=-\dfrac{5}{4}\)
d) \(\left|x+1,2\right|-1=2,2\\ \Rightarrow\left|x+1,2\right|=3,2\\ \Rightarrow\left[{}\begin{matrix}x+1,2=-3,2\\x+1,2=3,2\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=-4,4\\x=2\end{matrix}\right.\)
e) \(\Rightarrow\left|x+\dfrac{2}{3}\right|=\dfrac{1}{2}\\ \Rightarrow\left[{}\begin{matrix}x+\dfrac{2}{3}=-\dfrac{1}{2}\\x+\dfrac{2}{3}=\dfrac{1}{2}\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=-\dfrac{7}{6}\\x=-\dfrac{1}{6}\end{matrix}\right.\)
f) \(\Rightarrow\left|-x-0,1\right|=0,1\\ \Rightarrow\left[{}\begin{matrix}-x-0,1=0,1\\-x-0,1=-0,1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=-0,2\\x=0\end{matrix}\right.\)
câu 2:
a) \(x=\dfrac{2}{15}\)
b) \(x=\dfrac{5}{12}\)
c) \(x=\dfrac{39}{35}\)
d) \(x=\dfrac{5}{21}\)
e) \(x=-\dfrac{1}{44}\)
f) \(x=\dfrac{13}{21}\)
