1.       A. clear        B. teacher  C. reason    D. sea

2.       A. match     B. catch      C. choice     D. chemistry

3.    A. lesson        B. level        C. bigger    D. bed

Cho bthuc

A=\(\left(\dfrac{\sqrt{x}-2}{\sqrt{x}+2}-\dfrac{8\sqrt{x}}{4-x}\right):\dfrac{\sqrt{x}+2}{1-2\sqrt{x}}\) với x\(\ge0,x\ne4,x\ne\dfrac{1}{4}\)

a,RG A

b,Tìm x để A=\(-\dfrac{1}{3}\)

Tính 

A=\(\left(4+\dfrac{3+\sqrt{3}}{\sqrt{3}+1}\right)\left(4+\dfrac{3-\sqrt[]{3}}{1-\sqrt{3}}\right)\)

B=\(\dfrac{3\sqrt{2}-2\sqrt{5}}{3-\sqrt{10}}-\dfrac{\sqrt{15}-2\sqrt{5}}{2-\sqrt{3}}\)

Tính

A=\(\dfrac{4}{\sqrt{5}-2}-\dfrac{32}{\sqrt{5}+1}\)

B=\(\dfrac{10}{3\sqrt{2}-4}+\dfrac{28}{3\sqrt{2}+2}\)