Question

\(\sqrt{2X-5}+\sqrt{8X-20}=5\)

Answer 1

`\sqrt{2x-5}-\sqrt{8x-20}=5`           ĐKXĐ : `x>=5/2`

`<=>\sqrt{2x-5}-\sqrt{4(2x-5)}=5`

`<=>\sqrt{2x-5}-2\sqrt{2x-5}=5`

`<=>-\sqrt{2x-5}=5`

`<=>\sqrt{2x-5}=-5` ( vô lí )

Vậy pt đã cho vô nghiệm

Answer 2

Ta có: \(\sqrt{2x-5}+\sqrt{8x-20}=5\)

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

\(\Leftrightarrow\sqrt{2x-5}=\dfrac{5}{3}\)

\(\Leftrightarrow2x-5=\dfrac{25}{9}\)

\(\Leftrightarrow2x=\dfrac{70}{9}\)

hay \(x=\dfrac{35}{9}\)