1) \(\sqrt{4(x+1)}+\sqrt{9x+9}=10\) (1)
ĐKXĐ: \(\left\{ \begin{array}{l} 4(x+1)\ge 0\\ 9x+9\ge0 \end{array} \right .\Leftrightarrow x\ge -1\)
(1) \(\Rightarrow 2\sqrt{x+1}+3\sqrt{x+1}=10\)
\(\Rightarrow 5\sqrt{x+1}=10\)
\(\Rightarrow \sqrt{x+1}=2\)
\(\Rightarrow x+1=4\)
\(\Rightarrow x=3\) (tm).
2) \(\sqrt{x^2+2x+1}=5\) (2)
Ta có \(x^2+2x+1=(x+1)^2\ge 0\) \(\forall x\)
(2) \(\Rightarrow x^2+2x+1=25\)
\(\Rightarrow x^2+2x-24=0\)
\(\Rightarrow \left\{ \begin{array}{l} x=4 \\ x=-6\end{array} \right .\) (tm)
