Bài 2:
a: \(23+4\sqrt{15}=\left(2\sqrt{5}+3\right)^2\)
b: \(19-4\sqrt{15}=\left(\sqrt{15}-2\right)^2\)
c: \(10-2\sqrt{21}=\left(\sqrt{7}-\sqrt{3}\right)^2\)
d: \(22+2\sqrt{21}=\left(\sqrt{21}+1\right)^2\)
e: \(19-4\sqrt{21}=\left(2\sqrt{3}-\sqrt{7}\right)^2\)
f: \(31+4\sqrt{21}=\left(2\sqrt{7}+\sqrt{3}\right)^2\)
g: \(11-2\sqrt{30}=\left(\sqrt{6}-\sqrt{5}\right)^2\)
\(23+4\sqrt{15}=\left(2\sqrt{5}+\sqrt{3}\right)^2\)
\(19-4\sqrt{15}=\left(\sqrt{15}-2\right)^2\)
\(10-2\sqrt{21}=\left(\sqrt{7}-\sqrt{3}\right)^2\)
\(22+2\sqrt{21}=\left(\sqrt{21}+1\right)^2\)
\(19-4\sqrt{21}=\left(2\sqrt{3}-\sqrt{7}\right)^2\)
\(31+4\sqrt{21}=\left(2\sqrt{7}-\sqrt{3}\right)^2\)
\(11-2\sqrt{30}=\left(\sqrt{6}-\sqrt{5}\right)^2\)
Bài 1:
a: ĐKXĐ: \(x\ge\dfrac{5}{2}\)
b: ĐKXĐ: \(x\le3\)
c: ĐKXĐ: \(x>\dfrac{3}{4}\)
d: ĐKXĐ: \(x< 0\)
e: ĐKXĐ: \(x\ge\dfrac{1}{2}\)
f: ĐKXĐ: \(x\ge\dfrac{7}{2}\)
g: ĐKXĐ: \(\left\{{}\begin{matrix}x\le3\\x\ne0\end{matrix}\right.\)
h: ĐKXĐ: \(\left\{{}\begin{matrix}x< 0\\x\ne-1\end{matrix}\right.\)
