Question

\(x(2x-7)-4x+14=0\)

Answer 1

\(x\cdot\left(2x-7\right)-4x+14=0\)

\(\Leftrightarrow x\cdot\left(2x-7\right)-2\cdot\left(2x-7\right)=0\)

\(\Leftrightarrow\left(2x-7\right)\left(x-2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-7=0\\x-2=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=2\end{matrix}\right.\)

Answer 2

`x(2x-7)-4x+14=0`

`<=> 2x^2-7x-4x+14=0`

`<=> 2x^2-11x+14=0`

`<=> (2x^2-4x)-(7x-14)=0`

`<=>2x(x-2)-7(x-2)=0`

`<=>(2x-7)(x-2)=0`

`<=>` \(\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=2\end{matrix}\right.\)

Vậy `S={7/2 ; 2}`.

Answer 3

pt <=> 2x\(^2\)-7x-4x+14=0

<=> 2x\(^2\)-11x+14=0

<=> 2x\(^2\)-4x-7x+14=0

<=> (2x-7)(x-2)=0

<=> \(\left[{}\begin{matrix}x=2\\x=\dfrac{7}{2}\end{matrix}\right.\)