\(2x\left(x+1\right)-x\left(x+2\right)+x1=0\)
\(2x\left(x+1\right)-x\left(x+2-1\right)=0\) (đặt thừa số chung)
\(2x\left(x+1\right)-x\left(x+1\right)=0\)
\(\left(x+1\right)\left(2x-x\right)=0\)
\(\left(x+1\right)x=0\)
\(x=0\)\(x+1=0\Rightarrow x=-1\)