a, \(\left|x\right|+0,75=2\Rightarrow\left|x\right|=1,25\Rightarrow x=\pm1,25\)
b, \(\left|x+\dfrac{1}{3}\right|-4=1\Rightarrow\left|x+\dfrac{1}{3}\right|=5\Rightarrow\left|x\right|=\dfrac{14}{3}\Rightarrow x=\pm\dfrac{14}{3}\)
c,
\(\left|x\right|+2,5=0\Rightarrow\left|x\right|=-0,25\) (vô lí)
Vì \(\left|x\right|\ge0\) => x vô nghiệm
a) \(\left|x\right|+0,75=2\)
\(\Leftrightarrow\left|x\right|=2-0,75=1,25\)
\(\Rightarrow\left[{}\begin{matrix}x=-1,25\\x=1,25\end{matrix}\right.\)
b) \(\left|x+\dfrac{1}{3}\right|-4=1\)
\(\Leftrightarrow\left|x+\dfrac{1}{3}\right|=1+4=5\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{3}=5\\x+\dfrac{1}{3}=-5\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{14}{3}\\x=-\dfrac{16}{3}\end{matrix}\right.\)
c) \(\left|x\right|+2,5=0\)
\(\Leftrightarrow\left|x\right|=0-2,5=-2,5\)
Vì \(\left|x\right|\ge0\) mà \(-2,5< 0\) nên \(x\in\varnothing\)
