Question

\(\sqrt{4x-20}\)+\(\sqrt{x-5}\)-\(\dfrac{1}{3}\)\(\sqrt{9x-45}\)

Answer 1

\(\sqrt{4x-20}+\sqrt{x-5}-\dfrac{1}{3}\sqrt{9x-45}\)

\(=\sqrt{4\left(x-5\right)}+\sqrt{x-5}-\dfrac{1}{3}\sqrt{9\left(x-5\right)}\)

\(=2\sqrt{x-5}+\sqrt{x-5}-\dfrac{1}{3}\cdot3\sqrt{x-5}\)

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

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

Answer 2

ĐK: x>=5

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

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