\(x^2+7x+10=0\)
\(\left(x^2+2x\right)+\left(5x+10\right)=0\)
\(x\left(x+2\right)+5\left(x+2\right)=0\)
\(\left(x+2\right)\left(x+5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x+2=0\\x+5=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=-2\\x=-5\end{cases}}\)
Vậy \(\orbr{\begin{cases}x=-2\\x=-5\end{cases}}\)