\(a,2x^2+x=0\)
\(x\left(2x+1\right)=0\)
\(\left[{}\begin{matrix}x=0\\2x=-1\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=0\\x=-\frac{1}{2}\end{matrix}\right.\)
\(b,-0,4x^2+1,2x=0\)
\(x\left[\left(0,4x\right)-\left(1,2\right)\right]=0\)
\(\left[{}\begin{matrix}x=0\\0,4x-1,2=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=0\\0,4x=1,2\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=0\\x=\frac{3}{10}\end{matrix}\right.\)
\(c,7x^2-5x=0\)
\(x\left(7x-5\right)=0\)
\(\left[{}\begin{matrix}x=0\\7x-5=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=0\\x=\frac{5}{7}\end{matrix}\right.\)
\(e,-2x^2-11x=0\)
\(x\left(2x+11\right)=0\)
\(\left[{}\begin{matrix}x=0\\2x+11=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=0\\x=\frac{11}{2}\end{matrix}\right.\)