Question

√x^2-4x+13=3

Answer 1

\(\sqrt{x^2-4x+13}=3\)

\(ĐK:x\in R\)

\(\Leftrightarrow\text{​​}\)\(\left(\sqrt{x^2-4x+13}\right)^2=3^2\)

\(\Leftrightarrow x^2-4x+13=9\)

\(\Leftrightarrow x^2-4x+4=0\)

`<=>(x-2)^2=0`

`<=>x=2`

Vậy \(S=\left\{2\right\}\)

Answer 2

\(\sqrt{x^2-4x+13}=3\)

\(x^2-4x+13=9\)

\(x^2-4x+4=0\)

\(\left(x-2\right)^2=0\)

\(\Leftrightarrow x=2\)

Answer 3

\(\sqrt{x^2}-4x+13=3\\ \Leftrightarrow x-4x=-10\\ \Leftrightarrow-3x=-10\\ \Leftrightarrow x=\dfrac{10}{3}\)