\(x^2-3x+2=0\Leftrightarrow x^2-2x-x+2=0\Leftrightarrow x\left(x-2\right)-\left(x-2\right)=0\)
\(\Leftrightarrow\left(x-2\right)\left(x-1\right)=0\Leftrightarrow\)\(\left[\begin{matrix}x-2=0\\x-1=0\end{matrix}\right.\)\(\Leftrightarrow\left[\begin{matrix}x=2\\x=1\end{matrix}\right.\)
-----
\(x^2+5x+6=0\Leftrightarrow x^2+2x+3x+6=0\Leftrightarrow x\left(x+2\right)+3\left(x+2\right)=0\)
\(\Leftrightarrow\left(x+2\right)\left(x+3\right)=0\)\(\Leftrightarrow\left[\begin{matrix}x+2=0\\x+3=0\end{matrix}\right.\)\(\Leftrightarrow\left[\begin{matrix}x=-2\\x=-3\end{matrix}\right.\)
(x = 3) chia hết cho ( x - 1)
( 3x + 2 ) chia hết cho ( 2x - 1)
(x + 1) + (x+2) + ..... + (x+9) + (x+10) = 5
