Question

Giải PT: |-3x| = 4

Answer 1

\(\left|-3x\right|=4\)

\(\Leftrightarrow3\left|x\right|=4\)

\(\Leftrightarrow\left|x\right|=\dfrac{4}{3}\)

\(\Rightarrow x=\pm\dfrac{4}{3}\)

Answer 2

\(\left|-3x\right|=4\)

\(\Rightarrow-3x=\pm4\)

\(\Rightarrow\left[{}\begin{matrix}-3x=4\\-3x=-4\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{4}{3}\\x=\dfrac{4}{3}\end{matrix}\right.\)