a, 2x+x=3+5+4
3x=12
x=4
b, 2-2x=2018
-2x=2016
x=-1003
\(3-x+5=2x-4\)
\(\Rightarrow-x-2x=-4-5-3\)
\(\Rightarrow-3x=-12\)
\(\Rightarrow x=4\)
\(2\left|1-x\right|=2018\)
\(\Rightarrow\left|1-x\right|=1009\)
\(\Leftrightarrow\orbr{\begin{cases}1-x=1009\\1-x=-1009\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=-1008\\x=1010\end{cases}}\)
a, 2x+x=3+5+4
3x=12
x=4
b, 2-2x=2018
-2x=2016
x=-1003