Tìm x biết: x^2 - x - 6 = 0

$\text{x²-x-6=0}$

$\text{⇒x²+2x-3x-6=0}$

$\text{⇒(x²+2x)-(3x+6)=0}$

$\text{⇒x(x+2)-3(x+2)=0}$

$\text{⇒(x+2)(x-3)=0}$

$\text{⇒\(\left[ \begin{array}{l}x+2=0\\x-3=0\end{array} \right.\)}$

$\text{⇒\(\left[ \begin{array}{l}x=-2\\x=3\end{array} \right.\) }$