bài 1:
a: ĐKXĐ: \(x\ge-4\)
b: ĐKXĐ: \(x\ge-3\)
bài 2
a, \(3\sqrt{8}\) + \(\sqrt{18}\) - \(\sqrt{72}\)
=\(6\sqrt{2}\)+\(3\sqrt{2}\)-\(6\sqrt{2}\)
=\(3\sqrt{2}\)(3+1-3)
=3\(\sqrt{2}\)
Bài 3:
a: Ta có: \(\sqrt{x+2}=5\)
\(\Leftrightarrow x+2=25\)
hay x=23
b: Ta có: \(\sqrt{x-3}>2\)
\(\Leftrightarrow x-3>4\)
hay x>7