`3x^2-7x+4=0`
`<=> 3x^2 -3x-4x+4=0`
`<=> (3x^2-3x)-(4x-4)=0`
`<=> 3x(x-1)-4(x-1)=0`
`<=> (3x-4)(x-1)=0`
`<=>` \(\left[ \begin{array}{l}3x-4=0\\x-1=0\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}3x=4\\x=1\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=\frac{4}3\\x=1\end{array} \right.\)
Vậy `x=4/3` hoặc `x=1`