Question

Tính: Giúp em phần b và phần h với ạ

Answer 1

b) \(\sqrt{29-12\sqrt{5}}+\sqrt{45-20\sqrt{5}}=\sqrt{\left(2\sqrt{5}-3\right)^2}+\sqrt{\left(5-2\sqrt{5}\right)^2}=2\sqrt{5}-3+5-2\sqrt{5}=2\)

h) \(\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4+\sqrt{15}}=\left(\sqrt{10}-\sqrt{6}\right)\sqrt{\left(\sqrt{\dfrac{5}{2}}+\sqrt{\dfrac{3}{2}}\right)^2}=\left(\sqrt{10}-\sqrt{6}\right)\left(\sqrt{\dfrac{5}{2}}+\sqrt{\dfrac{3}{2}}\right)=\sqrt{25}+\sqrt{15}-\sqrt{15}-\sqrt{9}=5-3=2\)

Answer 2

h: Ta có: \(\left(\sqrt{10}-\sqrt{6}\right)\cdot\sqrt{4+\sqrt{15}}\)

\(=\left(\sqrt{5}-\sqrt{3}\right)\left(\sqrt{5}+\sqrt{3}\right)\)

=5-3=2

Answer 3