`a)` `-x+12=-2002`
`⇒-x=-2014`
`⇒x=2014`
`b)` `3(x+1)-6(x-5)=2(5-2x)`
`⇔3(x+1)-3(2x-10)=10-4x`
`⇔3(x+1-2x+10)=10-4x`
`⇔3(11-x)=10-4x`
`⇔33-3x=10-4x`
`⇔-3x+4x=10-33`
`⇔x=-23`
`c)` `(|x|-2)(x^2-4)=0`
`⇔` \(\left[ \begin{array}{l}|x|-2=0\\x^2-4=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}|x|=2\\x^2=4\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=2\\x=-2\end{array} \right.\)
Vậy `x=2` hoặc `x=-2`.
`d)` `|x+1|=|7-2x|`
`⇔|x+1|=7-2x`
`⇔` \(\left[ \begin{array}{l}x+1=7-2x\\x+1=-(7-2x)\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x+2x=7-1\\2x-x=-7-1\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}3x=6\\x=-8\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=2\\x=-8\end{array} \right.\)
Vậy `x=2` hoặc `x=-8`.
`e)` `|x+7|=3`
`⇔` \(\left[ \begin{array}{l}x+7=3\\x+7=-3\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=-4\\x+7=-10\end{array} \right.\)
Vậy `x=-4` hoặc `x=-10`.
