a) \(3x-\left(x+5\right)=2\left(x+1\right)\)
\(\Leftrightarrow2x-5=2x+2\) ( Pt vô nghiệm )
b) \(\left(2x-6\right)\left(x+5\right)-4x=2x^2-\left(x+1\right)\)
\(\Leftrightarrow2x^2-30=2x^2-x-1\)
\(\Leftrightarrow x=29\)
c) \(x+3\left(x+5\right)-6x=7\left(x+2\right)\)
\(\Leftrightarrow4x+15-6x=7x+14\)
\(\Leftrightarrow9x=1\)
\(\Leftrightarrow x=\frac{1}{9}\)