a) ĐKXĐ: \(x\ge-2\)
\(\sqrt{2x+4}=9\\ \Rightarrow2x+4=81\\ \Rightarrow x=38,5\left(tm\right)\)
b) ĐKXĐ: \(x\ge1\)
\(2\sqrt{4x-4}-\dfrac{1}{3}\sqrt{9x-9}+\dfrac{1}{5}\sqrt{25x-25}=8\\ \Rightarrow4\sqrt{x-1}-\sqrt{x-1}+\sqrt{x-1}=8\\ \Rightarrow4\sqrt{x-1}=8\\ \Rightarrow16x-16=64\\ \Rightarrow x=5\left(tm\right)\)
c) ĐKXĐ: \(\left\{{}\begin{matrix}x\ge\dfrac{5}{2}\\x\le-\dfrac{5}{2}\end{matrix}\right.\)
\(\sqrt{4x^2-25}-\sqrt{5}\sqrt{2x-5}=0\\ \Rightarrow\sqrt{4x^2-25}=\sqrt{10x-25}\Rightarrow4x^2-25=10-25\\ \Rightarrow4x^2=10x\\ \Rightarrow4x^2-10x=0\\ \Rightarrow2x\left(2x-5\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=0\left(ktm\right)\\x=\dfrac{5}{2}\left(tm\right)\end{matrix}\right.\)
