Question

[Hùng Chu]

Tính

a)\(\dfrac{2}{\sqrt{3}+1}-\dfrac{2}{\sqrt{3}-2}\)

b)\(\dfrac{4}{\sqrt{5}+2}+\dfrac{2}{\sqrt{5}+3}\)

Mọi ngì giải chi tiết giúp mik nha

Answer 1

[Nguyễn Lê Phước Thịnh]

a: Ta có: \(\dfrac{2}{\sqrt{3}+1}+\dfrac{2}{2-\sqrt{3}}\)

\(=\sqrt{3}-1+2+\sqrt{3}\)

\(=2\sqrt{3}+1\)

b: Ta có: \(\dfrac{4}{\sqrt{5}+2}+\dfrac{2}{3+\sqrt{5}}\)

\(=4\sqrt{5}-8+\dfrac{3}{2}-\dfrac{\sqrt{5}}{2}\)

\(=-\dfrac{13}{2}+\dfrac{7}{2}\sqrt{5}\)