Question

   giải giúp c d

Answer 1

c) Pt\(\Leftrightarrow\sqrt{4+x^2}=3-x\)

\(\Leftrightarrow\left\{{}\begin{matrix}3-x\ge0\\4+x^2=\left(3-x\right)^2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x\le3\\x=\dfrac{5}{6}\end{matrix}\right.\)\(\Rightarrow x=\dfrac{5}{6}\)

Vậy pt có nghiệm duy nhất \(x=\dfrac{5}{6}\)

d) Pt \(\Leftrightarrow\dfrac{1}{2}\sqrt{16\left(x-2\right)}-2\sqrt{4\left(x-2\right)}+\sqrt{9\left(x-2\right)}=5\)

\(\Leftrightarrow2\sqrt{x-2}-4\sqrt{x-2}+3\sqrt{x-2}=5\)

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

\(\Leftrightarrow x=27\) (tm)

Vậy...