\(x^2+5x-6=0\\ \Rightarrow x^2+6x-x-6=0\\ \Rightarrow x\left(x+6\right)-\left(x+6\right)=0\\ \Rightarrow\left(x-1\right)\left(x+6\right)=0\\ \Rightarrow\left[{}\begin{matrix}x-1=0\\x+6=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=1\\x=-6\end{matrix}\right.\\ \Rightarrow1\cdot\left(-6\right)=-6\\ \rightarrow D\)
cau16
\(-x^2-3x-2=0\Leftrightarrow-x^2-x-2x-2=0\)
\(\Leftrightarrow-x\left(x+1\right)-2\left(x+1\right)=0\)
\(\Leftrightarrow\left(-x-2\right)\left(x+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}-x=-2\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-1\end{matrix}\right.\Rightarrow A\)
