Question

tìm x biết 

x^2 - 15x =0

Answer 1

=>x(x-15)=0

=>x=0 hoặc x-15=0

=>x=0 hoặc x=15

Answer 2

\(x^2-15x=0\)

\(\Leftrightarrow x\left(x-15\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=15\end{matrix}\right.\)

Vậy \(S=\left\{0;15\right\}\)