a)\(\left\{{}\begin{matrix}\sqrt{2}x-\sqrt{3}y=1\\x+\sqrt{3}y=\sqrt{2}\end{matrix}\right.\)

b)\(\left\{{}\begin{matrix}x-2\sqrt{2}y=\sqrt{5}\\\sqrt{2}x+y=1-\sqrt{10}\end{matrix}\right.\)

c)\(\left\{{}\begin{matrix}\left(\sqrt{2}-1\right)x-y=\sqrt{2}\\x+\left(\sqrt{2}+1\right)y=1\end{matrix}\right.\)

d)\(\left\{{}\begin{matrix}\sqrt{3}x-\sqrt{2}y=1\\\sqrt{2}x+\sqrt{3}y=\sqrt{3}\end{matrix}\right.\)

giải phương trình

\(x\sqrt{x}-2\sqrt{x}-x=0\)

Tìm điều kiện của x để A dương :

A=\(\frac{3\sqrt{x}-6}{\sqrt{x}}\)

A=\(\frac{1}{\sqrt{x}\left(\sqrt{x}-2\right)}\)

Tìm các giá trị của x để A có giá trị âm

Cho tam giác ABC vuông tại A có AB=4\(\sqrt{3}\), AC=4 và đường phân giác BD

a)Tính BD

b)tính số đo góc B

c)chứng minh rằng AB+\(\frac{CD}{2}\)=BC

Rút gọn biểu thức:

a)\(\frac{2}{\sqrt{5}-\sqrt{3}}+\frac{3}{\sqrt{6}+\sqrt{3}}\)

b)\(\frac{3+2\sqrt{3}}{\sqrt{3}}+\frac{2+\sqrt{2}}{\sqrt{2}+1}-\left(2+\sqrt{3}\right)\)

c)\(\sqrt{3+\sqrt{5}}-\sqrt{3-\sqrt{5}}-\sqrt{2}\)

d)\(\left(1+tan^2a\right)\left(1-sin^2a\right)+\left(1+cotan^2a\right)\left(1-cos^2a\right)\)

Combine these sentences with who,whom,which:

1.Her mother listened to the news on TV. She was interested in weather forecasts.

2.Hoa took some change.She wanted to buy some drink

3.The boys are interested in football . It is a popular game all over the world

4.My classmates had so much fun at the carnival.They wanted to see it again

5.We visited the monument .It was built a hundred years ago

6.Minh went back home.He forgot to turn off the faucet

7.Mai wants to drink some medicine.She has a headache

8.Children like to eat cake.It can cause toothache if they have too much everyday

9.Her moon made a delicious for the family.She was a cook in a restaurant

10.The boy gave his parents big hugs before he left. He went aboard to study

a)\(\left(x^2+\frac{4}{x^2}\right)-4\left(x-\frac{2}{x}\right)-9=0\)

b)\(\left(\sqrt{x+5}-\sqrt{x+2}\right)\left(1+\sqrt{x^2+7x+10}\right)=3\)

A)\(\frac{6+2\sqrt{5}}{3-\sqrt{5}}-\frac{5+3\sqrt{5}}{\sqrt{5}}+\frac{\sqrt{5}}{2-\sqrt{5}}\)

B)\(\frac{8+2\sqrt{2}}{3-\sqrt{2}}-\frac{2+3\sqrt{2}}{\sqrt{2}}-\frac{3}{\sqrt{2}-1}\)

C)\(\frac{3+\sqrt{2}}{3-\sqrt{3}}-\frac{3+\sqrt{3}}{\sqrt{3}}-\frac{2}{\sqrt{3}-1}\)

D

\(\left(4-\sqrt{7}\right)\left(\sqrt{14}+\sqrt{2}\right)\sqrt{4+\sqrt{7}}\)