Bài 4:
a) Ta có: \(5\sqrt{12x}-4\sqrt{3x}+2\sqrt{48x}=14\)
\(\Leftrightarrow10\sqrt{3x}-4\sqrt{3x}+8\sqrt{3x}=14\)
\(\Leftrightarrow14\sqrt{3x}=14\)
\(\Leftrightarrow3x=1\)
hay \(x=\dfrac{1}{3}\)
b) Ta có: \(\sqrt{4x-20}+\sqrt{x-5}-\dfrac{1}{3}\sqrt{9x-45}=4\)
\(\Leftrightarrow2\sqrt{x-5}+\sqrt{x-5}-\sqrt{x-5}=4\)
\(\Leftrightarrow x-5=4\)
hay x=9
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