Question

Tìm x :  2x - 12 -  x  =0

              ( x - 7) . ( 2x - 8) = 0

Answer 1

\(2x-12-x=0\)

\(\Leftrightarrow2x-x=12\Leftrightarrow x=12\)

Answer 2

\(\left(x-7\right)\left(2x-8\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-7=0\\2x-8=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=7\\2x=8\end{cases}\Leftrightarrow\orbr{\begin{cases}x=7\\x=4\end{cases}}}\)

Answer 3

2x - 12 - x = 0

\(\Leftrightarrow\)2x - x = 12

\(\Leftrightarrow\)x=12

=))

Answer 4

\(\left(x-7\right).\left(2x-8\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-7=0\\2x-8=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=7\\2x=8\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=7\\x=4\end{cases}}}\)

Vậy \(x\in\left\{7;4\right\}\)

Answer 5

( x - 7) . ( 2x - 8) = 0

\(\Leftrightarrow\orbr{\begin{cases}x-7=0\\2x-8=0\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}x=0+7\\2x=8\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}x=7\\x=4\end{cases}}\)

Vậy:.............................