Question

\(\sqrt{\text{4x-20}}+\sqrt{x-5}=6\)

Answer 1

\(ĐK:x\ge5\)

\(\Leftrightarrow\sqrt{4\left(x-5\right)}+\sqrt{x-5}=6\)

\(\Leftrightarrow2\sqrt{x-5}+\sqrt{x-5}=6\)

\(\Leftrightarrow3\sqrt{x-5}=6\)

\(\Leftrightarrow\sqrt{x-5}=2\)

\(\Leftrightarrow x-5=4\)

\(\Leftrightarrow x=9\) (tm)

S = {9}

Answer 2

\(\sqrt{4x-20}\) +\(\sqrt{x-5}\)=6

\(\sqrt{4\left(x-5\right)}\) + \(\sqrt{x-5}\) = 6

2\(\sqrt{x-5}\) + \(\sqrt{x-5}\) =6

3\(\sqrt{x-5}\) =6

\(\sqrt{x-5}\) =2

x - 5 = 4

x =9