a) \(xy^2-2xy+x=x\left(y^2-2y+1\right)=x\left(y-1\right)^2\)
b) \(x^2-xy+x-y=x\left(x-y\right)+\left(x-y\right)=\left(x+1\right)\left(x-y\right)\)
a) \(x^4-2x^2=0\)
⇔ \(x^2\left(x^2-2\right)=0\)
⇔ \(x^2\left(x-\sqrt{2}\right)\left(x+\sqrt{2}\right)=0\)
⇔ \(\left[{}\begin{matrix}x=0\\x=\pm\sqrt{2}\end{matrix}\right.\)
b) \(x^2+3x+2=0\)
\(\Leftrightarrow x\left(x+1\right)+2\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(x+2\right)=0\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-2\end{matrix}\right.\)
