Đáp án:
Giải thích các bước giải:
a) `|x| = 2,5`
`⇔` \(\left[ \begin{array}{l}x=2,5\\x=-2,5\end{array} \right.\)
b) `|x| = -1,2` (vô lí)
c) `|x| + 0,573 = 2`
`⇔ |x|=1,427`
`⇔` \(\left[ \begin{array}{l}x=1,427\\x=-1,427\end{array} \right.\)
d) `|x + 1/3 |−4=−1`
`⇔ |x + 1/3 |=3`
`⇔` \(\left[ \begin{array}{l}x+\dfrac{1}{3}=3\\x+\dfrac{1}{3}=-3\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=\dfrac{8}{3}\\x=-\dfrac{10}{3}\end{array} \right.\)