a, `|x + 2| = 6 - 4`
`|x - 2| = 2`
`⇒` \(\left[ \begin{array}{l}x-2=2\\x-2=-2\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}x=2-2\\x=-2-2\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}x=0\\x=-4\end{array} \right.\)
b, `|x| + 1 = 4`
`|x| = 4 - 1`
`|x| = 3`
`⇒` \(\left[ \begin{array}{l}x=3\\x=-3\end{array} \right.\)
c, `x + 2x + 3x = 12`
`6x = 12`
`x = 12 ÷ 6`
`x = 2`
Xin hay nhất !