1, I began learning E 3years ago

2,I did 4 exercises last night

3,He telephone her at 2 o'clock

4,He was in VN for 10 years

5,I got up at halp past five

6,I had bread and omeletes this morning

7,I left home at 6 o' clock

8,I went to school this morning by bicycle

9,I watched television after...

10,I went to bed last night at 10 o'clock

3.C

6.A

8.D

9.B

10.D

3c

6a

8c

9b

10d

1 traditional

2 geological

3 recognized

4 illiterate

VII

1 A

2 B

3 A

4 A

2. BCNN(15,88)=1320

BCNN(45,120,36)=360

BCNN(28,30,98)=2940

Bài 3: 

3=3

8=2³

16=2⁴

84=2²x3x7

120=2³x3x5

145=5x29

Câu 2 : C

Câu 3 : A

Câu 4 : C

Câu 5 : C

Câu 6 : B

Câu 7 : C

Câu 8 : D

Câu 9 : B

Câu 2: C

Pt\(\Leftrightarrow\left\{{}\begin{matrix}x-2\ge0\\x^2+5x-2=\left(x-2\right)^2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x\ge2\\9x=6\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x\ge2\\x=\dfrac{6}{9}\end{matrix}\right.\)\(\Rightarrow x\in\varnothing\)

Câu 3: A

\(\Delta:3x+4y-11=0\)

\(d_{\left(M;\Delta\right)}=\dfrac{\left|3.1+4.-1-11\right|}{\sqrt{3^2+4^2}}=\dfrac{12}{5}\)

Câu 4: Ko có đ/a

Do \(\dfrac{\pi}{2}< \alpha< \pi\Rightarrow tan\alpha< 0;cot\alpha< 0;cos\alpha< 0\)

\(1+cot^2\alpha=\dfrac{1}{sin^2\alpha}\)\(\Rightarrow cot\alpha=\dfrac{-\sqrt{21}}{2}\)

Câu 5:C

Câu 6:B

Câu 7: A

Có nghiệm khi \(\left(m;+\infty\right)\cup\left[-2;2\right]\ne\varnothing\) 

\(\Leftrightarrow m< 2\)

Câu 8:D

Câu 9: B

\(cos2\alpha=2cos^2\alpha-1=-\dfrac{23}{25}\)

Câu 10:D