\(B=\sqrt{16+8\sqrt{7}+7}-\sqrt{7}\)

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

\(=4+\sqrt{7}-\sqrt{7}\\ =4\)

\(A=\sqrt{7}-2+\sqrt{7}-5\\ =2\sqrt{7}-7\\ =\sqrt{7}\left(2-\sqrt{7}\right)\)

\(C=\sqrt{\sqrt{5}-\sqrt{3-\sqrt{20-12\sqrt{5}+9}}}\)

\(=\sqrt{\sqrt{5}-\sqrt{3-\sqrt{\left(2\sqrt{5}-3\right)^2}}}\)

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

\(=\sqrt{\sqrt{5}-\sqrt{5-2\sqrt{5}+1}}\)

\(=\sqrt{\sqrt{5}-\sqrt{\left(\sqrt{5}-1\right)^2}}\)

\(=\sqrt{\sqrt{5}-\sqrt{5}+1}\)
\(=\sqrt{1}\\ =1\)

\(B=\sqrt{25+2\sqrt{75}+3}+\sqrt{16-2\sqrt{48}+3}\)

\(=\sqrt{\left(5+\sqrt{3}\right)^2}+\sqrt{\left(4-\sqrt{3}\right)^2}\)

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

\(=9\)

\(A=\sqrt{9-6\sqrt{7}+7}+\sqrt{3-2\sqrt{21}+7}\)

\(=\sqrt{\left(3-\sqrt{7}\right)^2}+\sqrt{\left(\sqrt{7}-\sqrt{3}\right)^2}\)

\(=3-\sqrt{7}+\sqrt{7}-\sqrt{3}\)

\(=3-\sqrt{3}\)

Tomorrow (be) is her birthday .she (invite) is going to invite some friends to her house.

- let's (go) go out.

My name is Minh. Last summer, my family went to Hue by train. My family came to visit our grandparents. We visited Hue Citadel. My trip is amazing.

1, My son went to the supermarket but he hasn't come back ( not come back) yet.

2, The businessman has worked (work) in the same office for twenty five years.

3, Miriam has lived (live) in Japan since she was five years old.

4, The woman wants to sell her house but she hasn't sold ( not sell ) it.

5, Why don't you want to play football with us this weekend ? I ( break) have broken my leg.

1, \(3x^2-2x\left(5+1,5x\right)+10\)

= \(3x^2-10x-3x^2+10\)

= \(10-10x\)

= \(10\left(1-x\right)\)

3. Children / speak Chinese? speak Chinese / friends

A: How do the children practice speaking Chinese?

B: They speak Chinese with their friends.