Câu 1:
ĐKXĐ: \(4x+3\ge0\Leftrightarrow x\ge-\dfrac{3}{4}\)
Câu 2:
a) \(\sqrt{49}-\sqrt{169}=7-13=-6\)
b) \(=\sqrt{2}-1-\sqrt{2}=-1\)
Câu 3:
a) ĐKXĐ: \(x\ge0\)
\(pt\Leftrightarrow\sqrt{5x}=\sqrt{45}\)
\(\Leftrightarrow5x=45\Leftrightarrow x=9\left(tm\right)\)
b) \(pt\Leftrightarrow\left|3x-2\right|=7\)
\(\Leftrightarrow\left[{}\begin{matrix}3x-2=7\\3x-2=-7\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{5}{3}\end{matrix}\right.\)
\(1,ĐK:x\ge-\dfrac{3}{4}\\ 2,\\ a,=7-13=-6\\ b,=\sqrt{2}-1-\sqrt{2}=-1\\ 3,\\ a,ĐK:x\ge0\\ PT\Leftrightarrow\sqrt{5x}=\sqrt{45}=3\sqrt{5}\\ \Leftrightarrow\sqrt{x}=3\Leftrightarrow x=9\left(tm\right)\\ b,\Leftrightarrow\left|3x-2\right|=7\Leftrightarrow\left[{}\begin{matrix}3x-2=7\\3x-2=-7\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{5}{3}\end{matrix}\right.\)
