Question

Tìm x biết: x^3+6x^2+9x=0

Answer 1

Ta có: \(x^3+6x^2+9x=0\)

\(\Leftrightarrow x\left(x+3\right)^2=0\)

hay \(x\in\left\{0;-3\right\}\)

Answer 2

x³+6x²+9x=0

⇒x(x²+6x+9)=0

⇒x(x+3)²=0

⇒\(\left[{}\begin{matrix}x=0\\\left(x+3\right)^2=0\end{matrix}\right.\)

⇒\(\left[{}\begin{matrix}x=0\\x+3=0\end{matrix}\right.\)

⇒\(\left[{}\begin{matrix}x=0\\x=-3\end{matrix}\right.\)

Answer 3

\(pt< =>x\left(x^2+6x+9\right)=0< =>x\left(x+3\right)^2=0\)

\(=>\left[{}\begin{matrix}x=0\\x=-3\end{matrix}\right.\)

Answer 4

x³ + 6x² + 9x =0

x³ + 3x² + 3x² + 9x=0

x²(x+3) + 3x(x+3) =0

(x+3)(x²+3x)=0

x(x+3)(x+3)=0

x(x+3)² =0

+) x =0

+) (x+3)² =0 

\(\Rightarrow\)x+3=0 

\(\Rightarrow\)x=-3

Vậy x =-3 hoặc x =0