a) Ta có: \(4\left(x-2\right)-2\left(x+3\right)=-28\)
\(\Leftrightarrow4x-8-2x-6+28=0\)
\(\Leftrightarrow2x+14=0\)
\(\Leftrightarrow2x=-14\)
hay x=-7
Vậy: x=-7
b) Ta có: \(3x+7-9x=-11\)
\(\Leftrightarrow-6x+7+11=0\)
\(\Leftrightarrow-6x+18=0\)
\(\Leftrightarrow-6x=-18\)
hay x=3
Vậy: x=3