Question

х²-9х=0.............

Answer 1

$x^2-9x=0~;\\x\cdot(x-9)=0~;\\\left [ \begin{array}{ccc} x=0 \\\\ x-9=0 \end{array}\right\Rightarrow \bf \left [ \begin{array}{ccc} x_1=0 \\\\ x_2=9. \end{array}\right$