a,ĐK:\(x\ge-1\)
\(3\sqrt{4\left(x+1\right)}-\sqrt{9\left(x+1\right)}-\dfrac{8}{16}\sqrt{x+1}=5\)
\(\Leftrightarrow6\sqrt{x+1}-3\sqrt{x+1}-\dfrac{1}{2}\sqrt{x+1}=5\)
\(\Leftrightarrow\dfrac{5}{2}\sqrt{x+1}=5\Leftrightarrow\sqrt{x+1}=2\)
\(\Leftrightarrow x+1=4\Leftrightarrow x=3\)
Vậy nghiệm của pt S=\(\left\{3\right\}\)
b,ĐK:\(x\ge-1\) và \(x\ge\dfrac{-5}{2}\)
\(\Leftrightarrow2x+5=x+1\)
\(\Leftrightarrow x=-4\)(k tm)
vậy pt vô nghiệm
c,Ta có:
\(\sqrt{\left(x-3\right)^2}=9\)
\(\Leftrightarrow\left|x-3\right|=9\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=9\\x-3=-9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=12\\x=-6\end{matrix}\right.\)
Vậy pt có nghiệm S=\(\left\{12;-6\right\}\)
