Question

2) Giải phương trình
 \(\sqrt{4+3\sqrt{x}}=5\)

Answer 1

ĐK: x≥0

\(pt\Rightarrow4+3\sqrt{x}=25\Leftrightarrow\sqrt{x}=7\Leftrightarrow x=49\left(tmđk\right)\)

Answer 2

\(\sqrt{4+3\sqrt{x}}=5\) (ĐK: \(x\ge0\))

\(\Leftrightarrow4+3\sqrt{x}=5^2\)

\(\Leftrightarrow4+3\sqrt{x}=25\)

\(\Leftrightarrow3\sqrt{x}=25-4\)

\(\Leftrightarrow3\sqrt{x}=21\)

\(\Leftrightarrow\sqrt{x}=\dfrac{21}{3}\)

\(\Leftrightarrow\sqrt{x}=7\)

\(\Leftrightarrow x=7^2\)

\(\Leftrightarrow x=49\left(tm\right)\)

Vậy \(x=49\)