Question

Answer 1

a: Ta có: \(\sqrt{\left(3\sqrt{3}-4\right)^2}-\sqrt{\left(5-4\sqrt{3}\right)^2}\)

\(=3\sqrt{3}-4-4\sqrt{3}+5\)

\(=-\sqrt{3}+1\)

b: Ta có: \(\left(2\sqrt{28}-3\sqrt{175}+4\sqrt{63}-7\sqrt{2\dfrac{2}{7}}\right):6\sqrt{7}\)

\(=\left(4\sqrt{7}-15\sqrt{7}+12\sqrt{7}-4\sqrt{7}\right):6\sqrt{7}\)

\(=-\dfrac{1}{2}\)

Answer 2

Bài 3: 

Ta có: \(\sqrt{9x-27}-5\sqrt{4x-12}+3\sqrt{25x-75}=16\)

\(\Leftrightarrow3\sqrt{x-3}-10\sqrt{x-3}+15\sqrt{x-3}=16\)

\(\Leftrightarrow8\sqrt{x-3}=16\)

\(\Leftrightarrow x-3=4\)

hay x=7