Đáp án:
Giải thích các bước giải:
$a)x^2-10x=0$
$⇔x(x-10)=0$
\(\left[ \begin{array}{l}x=0\\x-10=0\end{array} \right.\)
\(\left[ \begin{array}{l}x=0\\x=10\end{array} \right.\)
$b)8x^2-72x=0$
$⇔8x(x-9)=0$
\(\left[ \begin{array}{l}8x=0\\x-9=0\end{array} \right.\)
\(\left[ \begin{array}{l}x=0\\x=9\end{array} \right.\)
$c)x^2+9x =0$
$⇔x(x+9) =0$
\(\left[ \begin{array}{l}x=0\\x+9=0\end{array} \right.\)
\(\left[ \begin{array}{l}x=0\\x=-9\end{array} \right.\)
