Question

Answer 1

a, -\(\sqrt{3}\) \(-\) \(\sqrt{7-4\sqrt{3}}\)

= -\(\sqrt{3}\) \(-\) \(\sqrt{4-2\sqrt{3}+3}\)

= -\(\sqrt{3}\) \(-\) \(\sqrt{\left(2-\sqrt{3}\right)^2}\)

= -\(\sqrt{3}\) \(-\) \(\left(2-\sqrt{3}\right)\) \(\)(do 2\(-\sqrt{3}\ge0\))

= -\(\sqrt{3}\) \(-2\)\(+\sqrt{3}\)

= -2

 

Answer 2

a: \(-\sqrt{3}-\sqrt{7-4\sqrt{3}}\)

\(=-\sqrt{3}-\sqrt{\left(2-\sqrt{3}\right)^2}\)

\(=-\sqrt{3}-\left(2-\sqrt{3}\right)=-\sqrt{3}-2+\sqrt{3}=-2\)

b: ĐKXĐ: x>=0

\(\sqrt{2x}=\left(\sqrt{5}-1\right)\left(\sqrt{5}+1\right)\)

=>\(\sqrt{2x}=5-1=4\)

=>2x=16

=>x=8(nhận)