`x(x - 2) + 4x - 8 = 0`
`⇔ x^2−2x+4x−8=0`
`⇔ x^2+2x−8=0`
`⇔` \(\left[ \begin{array}{l}a+b=2\\ab=-8\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}-1,8\\-2,4\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}-1+8=7\\-2+4=2\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}a=-2\\b=4\end{array} \right.\)
`⇔ (x−2)(x+4)`
`⇔` \(\left[ \begin{array}{l}x=2\\x=-4\end{array} \right.\)
Cho mình xin hay nhất nha bạn!!!
@Drew Mclntyre
