Question

\(x^2\)+x=0

Answer 1

\(x^2+x=0\)

\(\Rightarrow x\left(x+1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)

Vậy: \(S=\left\{0;-1\right\}\)

 

Answer 2

x² + x = 0

=) x(x + 1) = 0

=) x = 0 hoặc x + 1 = 0

=) x = 0 hoặc x = -1.

=) x ∈ { 0;-1}