`4x^2-9x=0`
`⇔ x(4x−9)=0`
\(\left[ \begin{array}{l}x=0\\x=\dfrac{9}{4}\end{array} \right.\)
`x^2 - 7x+6=0`
`⇔` \(\left[ \begin{array}{l}a+b=−7\\ab=6\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}−1,−6\\-2,-3\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}−1−6=−7\\−2−3=−5\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}a=-6\\b=−1\end{array} \right.\)
`⇔ (x−6)(x−1)`
\(\left[ \begin{array}{l}x=6\\x=1\end{array} \right.\)
`3x^2+5x-8=0`
`⇔` \(\left[ \begin{array}{l}a+b=5\\ab=3(−8)=−24\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}−1,24\\−2,12\\−3,8\\−4,6\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}−1+24=23\\−2+12=10\\−3+8=5\\−4+6=2\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}a=−3\\b=8\end{array} \right.\)
`⇔ (3x^2−3x)+(8x−8)`
`⇔ 3x(x−1)+8(x−1)`
`⇔ (x−1)(3x+8)`
\(\left[ \begin{array}{l}x=1\\x=-\dfrac{8}{3} \end{array} \right.\)
Cho mình xin hay nhất nha bạn
@Drew Mclntyre
