Question

\(\sqrt{x+9}+\sqrt{x+9}=0\)

Answer 1

\(\sqrt{x+9}+\sqrt{x+9}=0\)

\(\Leftrightarrow2\sqrt{x+9}=0\)

\(\Leftrightarrow\sqrt{x+9}=0:2\)

\(\Leftrightarrow\sqrt{x+9}=0\)

\(\Leftrightarrow\left(\sqrt{x+9}\right)^2=0^2\)

\(\Leftrightarrow x+9=0\)

\(\Leftrightarrow x=0-9\)

\(\Rightarrow x=-9\)

Answer 2

\(\sqrt{x+9}+\sqrt{x+9}=0\)

\(2\sqrt{x+9}=0\)

\(\sqrt{x+9}=0\text{ : }2\)

\(\sqrt{x+9}=0\)

\(\left(\sqrt{x+9}\right)^2=0^2\)

\(x+9=0\)

\(x=0-9\)

\(x=-9\)