Question

2.Tìm x

a)Căn x^2 -6x +9

 

Answer 1

Mn giúp e với ak

Answer 2

\(\sqrt{x^2-6x+9}\)

\(=\)\(\sqrt{\left(x^2-2.3x+3^2\right)}\)

\(=\sqrt{\left(x-3\right)^2}\)

\(=x-3\)

⇒ x∈R

Answer 3

\(\sqrt{x^2-6x+9}=\sqrt{\left(x-3\right)^2}=\left|x-3\right|=\left[{}\begin{matrix}x-3,\forall x\ge0\\3-x,\forall x< 0\end{matrix}\right.\)