a) \(x+5x^2=0\)
\(=>x\left(1+5x\right)=0\)
\(=>\hept{\begin{cases}x=0\\5x+1=0\end{cases}}\)
\(=>\hept{\begin{cases}x=0\\x=\frac{-1}{5}\end{cases}}\)
b) \(x^3+x=0\)
\(=>x\left(x^2+1\right)=0\)
\(=>\hept{\begin{cases}x=0\\x^2+1=0\end{cases}}\)
\(=>\hept{\begin{cases}x=0\\x\in\phi\end{cases}}\)
c) \(5x\left(x-1\right)=x-1\)
\(=>5x\left(x-1\right)-x+1=0\)
\(=>5x\left(x-1\right)-\left(x-1\right)=0\)
\(=>\left(x-1\right)\left(5x-1\right)=0\)
\(=>\hept{\begin{cases}x-1=0\\5x-1=0\end{cases}}\)
\(=>\hept{\begin{cases}x=1\\x=\frac{1}{5}\end{cases}}\)
d) \(x^2-10x=-25\)
\(=>x^2-10x+25=0\)
\(=>\left(x-5\right)^2=0\)
\(=>x-5=0\)
\(=>x=5\)
\(a,x+5x^2=0\)
\(x.\left(1+5x\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\1+5x=0\end{cases}}\) \(\Leftrightarrow\orbr{\begin{cases}x=0\\x=\frac{-1}{5}\end{cases}}\)
