\(x^2+5x-14=0\)
\(\Rightarrow x^2+7x-2x-14=0\)
\(\left(x^2+7x\right)-\left(2x+14\right)=0\)
\(x\left(x+7\right)-2\left(x+7\right)=0\)
\(\Rightarrow\left(x-2\right)\left(x+7\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-2=0\\x+7=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=2\\x=-7\end{cases}}\)
Vậy \(\orbr{\begin{cases}x=2\\x=-7\end{cases}}\)
\(x^2-5x-14=0\)
\(\Leftrightarrow\)\(x^2+2x-7x-14=0\)
\(\Leftrightarrow\)\(x\left(x+2\right)-7\left(x+2\right)=0\)
\(\Leftrightarrow\)\(\left(x-7\right)\left(x+2\right)=0\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x-7=0\\x+2=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=7\\x=-2\end{cases}}}\)
