\(a,=\sqrt{\left(\sqrt{3}\right)^2+2.\sqrt{3}.\sqrt{2}+\left(\sqrt{2}\right)^2}-\sqrt{\left(\sqrt{3}\right)^2-2.\sqrt{3}.\sqrt{2}+\left(\sqrt{2}\right)^2}\\ =\sqrt{\left(\sqrt{3}+\sqrt{2}\right)^2}-\sqrt{\left(\sqrt{3}-\sqrt{2}\right)^2}\\ =\left|\sqrt{3}+\sqrt{2}\right|-\left|\sqrt{3}-\sqrt{2}\right|\\ =\sqrt{3}+\sqrt{2}-\left(\sqrt{3}-\sqrt{2}\right)\\ =\sqrt{3}+\sqrt{2}-\sqrt{3}+\sqrt{2}\\=2\sqrt{2} \)

\(b,=\sqrt{\left(\sqrt{3}\right)^2+2.\sqrt{3}.1+1}+\sqrt{\left(\sqrt{3}\right)^2-2.\sqrt{3}.1+1}\\ =\sqrt{\left(\sqrt{3}+1\right)^2}+\sqrt{\left(\sqrt{3}-1\right)^2}\\ =\left|\sqrt{3}+1\right|+\left|\sqrt{3}-1\right|\\ =\sqrt{3}+1+\sqrt{3}-1\\ =2\sqrt{3}\)

\(c,=x-4+\sqrt{\left(4^2-2.4.x+x^2\right)}\\ =x-4+\sqrt{\left(4-x\right)^2}\\ =x-4+\left|4-x\right|\\ =x-4+x-4=2x-8\)    (vì \(x>4\) )

@seven 

600/9702 = 100/1617

\(\frac{600}{9702}=\frac{600:6}{9702:6}=\frac{100}{1617}\)

\(\frac{600}{9702}=\frac{100}{1617}\)

2 have been reading - haven't finished

3 have gone

4 am going to have

5 have washed

6 have broken

7 add - mix

8 have used

9 have lived

10 is always doing

11 am going

12 has taught

13 have already bought

14 always meet

4 đáp án là A,B,C,D nhé

1 B

2 D

3 D

4 B

5 A

6 C

7 D

8 A

9 C

1 She advised him to go on holiday when the weather got warmer

2 She warned them to keep out of that room at all time

3 He reminded me to post those letter

4 He asked them not to go into his study

5 I told him not to wait for me

7 She advised him not to go on holiday yet

8 She warned them against entering that room

1 D

2 A

3 C

4 A

5 B

6 C

7 C

8 C

9 A

10 A

^A =130 

^B =130 

mà 2 góc này ở vị trí sole trong 

⇒a//y(1)

^O=180⇒^O1=180-130

⇒^O1=50 

Mà Ox là  tia phân giác ⇒ ^O1=^O2=50

⇒^O2=B=50

Mà 2 góc này ở vị tri sole trong 

⇒y//b(2)

Từ (1)(2)⇒a//b

A nhá