Question

Giải phương trình :

a) \(\sqrt{2x^2-\sqrt{2}x+\dfrac{1}{4}}=\sqrt{2}x\)

b)\(\sqrt{4x+8}+\dfrac{1}{3}\sqrt{9x+18}=3\sqrt{\dfrac{x+2}{4}}+\sqrt{2}\)

Answer 1

Answer 2

Answer 3

b: Ta có: \(\sqrt{4x+8}+\dfrac{1}{3}\sqrt{9x+18}=3\sqrt{\dfrac{x+2}{4}}+\sqrt{2}\)

\(\Leftrightarrow2\sqrt{x+2}+\dfrac{1}{3}\cdot3\sqrt{x+2}-\dfrac{3}{2}\sqrt{x+2}=\sqrt{2}\)

\(\Leftrightarrow\sqrt{x+2}\cdot\dfrac{3}{2}=\sqrt{2}\)

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

\(\Leftrightarrow x+2=\dfrac{8}{9}\)

hay \(x=-\dfrac{10}{9}\)