Question

Tìm x\(\varepsilon\) Z:

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

Nhanh mk tk cho 3 cái

Answer 1

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

Answer 2

\(\hept{\begin{cases}x-7=0\\x+8=0\end{cases}}suyra\hept{\begin{cases}x=7\\x=-8\end{cases}}xongroido\)

Answer 3

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

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

Answer 4

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

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

Vậy ...