\(20-[7(x-3)+4]=2\)
\(7(x-3)+4=20-2\)
\(7(x-3)+4=18\)
\(7(x-3)=18-4\)
\(7(x-3)=14\)
\(x-3=14:7\)
\(x-3=2\)
\(x=2+3=5\)
\(20-\left[7\left(x-3\right)+4\right]=2\)
\(\Leftrightarrow7\left(x-3\right)+4=18\)
\(\Leftrightarrow7\left(x-3\right)=14\)
\(\Leftrightarrow x-3=2\)
\(\Leftrightarrow x=5\)
Vậy x = 5