( x + 5 ) . ( x + 6 ) = 0
\(\Leftrightarrow\left\{{}\begin{matrix}x+5=0\\x+6=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-5\\x=-6\end{matrix}\right.\)
Vậy \(x=-5\) hoặc \(x=-6\)
8x - 9x -2x - 15 = 0
\(\Rightarrow8x-9x-2x=0+15\)
\(\Rightarrow-3x=15\)
\(\Rightarrow x=15:\left(-3\right)\)
\(\Rightarrow x=-5\)
a, \(\left(x+5\right)\left(x+6\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+5=0\\x+6=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=-6\end{matrix}\right.\)
Vậy ......
\(\left(x+5\right)\left(x+6\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x+5=0\\x+6=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=-5\\x=-6\end{matrix}\right.\)
\(8x-9x-2x-15=0\)
\(\Rightarrow8x-9x-2x=15\)
\(\Rightarrow-3x=15\)
\(\Rightarrow x=-5\)
