1) Ta có: \(3\left(x-1\right)-5x=9\left(x+4\right)-20\)
\(\Leftrightarrow-2x-3=9x+16\)
\(\Leftrightarrow-11x=19\)
hay \(x=-\dfrac{19}{11}\)
2: Ta có: \(4\left(3x+2\right)-3\left(x-4\right)=9x+20\)
\(\Leftrightarrow12x+8-3x+12-9x-20=0\)
\(\Leftrightarrow0x=0\)(luôn đúng