1 Yesterday was cooler than today

2 Salim is the most beautiful in her team

3 His house is the highest in my city

4 No one in her class is as intelligent as Lan

5 BJ is one of the greatest tennis players in the world

1. Yesterday was colder than today.

2. Salim is the most beautiful in her team.

3. His house is the highest house in my city.

4.No one in her class is more intelligent than Lan

8. BJ isthe greatest tennis player in the world.

Đề bài đây ạ 

N S R I

\(i=120^o-90^o=30^o\)

\(i=i'\Leftrightarrow i'=30^o\)

Câu 14:

a: Thay x=36 vào B, ta được:

\(B=\frac{6-3}{6+1}=\frac37\)

b: \(A=\frac{2\sqrt{x}}{\sqrt{x}+3}+\frac{\sqrt{x}+1}{\sqrt{x}-3}+\frac{3-11\sqrt{x}}{9-x}\)

\(=\frac{2\sqrt{x}\cdot\left(\sqrt{x}-3\right)+\left(\sqrt{x}+1\right)\left(\sqrt{x}+3\right)+11\sqrt{x}-3}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)

\(=\frac{2x-6\sqrt{x}+x+4\sqrt{x}+3+11\sqrt{x}-3}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=\frac{3x+9\sqrt{x}}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)

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

Câu 12:

a: Thay x=49 vào A, ta được:

\(A=\frac{49-4}{\sqrt{49}-2}=\frac{45}{7-2}=\frac{45}{5}=9\)

b: \(B=\frac{2}{\sqrt{x}-2}+\frac{3}{\sqrt{x}+2}-\frac{x-5\sqrt{x}+2}{4-x}\)

\(=\frac{2\left(\sqrt{x}+2\right)+3\left(\sqrt{x}-2\right)+x-5\sqrt{x}+2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\)

\(=\frac{2\sqrt{x}+4+3\sqrt{x}-6+x-5\sqrt{x}+2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}=\frac{x}{x-4}\)