1.      What size shoes do you take?

2.      What newspaper do you read?

3.      What color are your eyes?

4.      What time did you arrive this morning?

5.      What kind of film do you like?

6.      How tall is your teacher?

7.      How far is it from your house to the office?

8.      How much did you pay for your new shirt?

9.      How often do you take an English test in class?

10.  How long have you been studying English?

1 was given

2 have repaired

3 had finished

4 isn't reading

5 had talked

1 was found

2 are always

8 ko có từ

9 have become

10 had met

11 aren't

12 arrives

13 is repairing

14 was built

15 had finished

16 will stay

a: Xét (O) có

MA là tiếp tuyến

MB là tiếp tuyến

Do đó: MA=MB

hay M nằm trên đường trung trực của AB(1)

Ta có: OA=OB

nên O nằm trên đường trung trực của AB(2)

Từ (1) và (2) suy ra OM⊥AB

a: Δ=(m-2)^2-4(m-4)

=m^2-4m+4-4m+16

=m^2-8m+20

=m^2-8m+16+4

=(m-2)^2+4>=4>0

=>Phương trình luôn có 2 nghiệm pb

b: x1^2+x2^2

=(x1+x2)^2-2x1x2

=(m-2)^2-2(m-4)

=m^2-4m+4-2m+8

=m^2-6m+12

=(m-3)^2+3>=3

Dấu = xảy ra khi m=3

a: góc CAO+góc CMO=180 độ

=>CAOM nội tiếp

b: Xét (O) có

CA,CM là tiếp tuyến

=>CA=CM và OC là phân giác của góc MOA(1)

Xét (O) co

DM,DB là tiếp tuyến

=>DM=DB và OD là phân giác của góc MOB(2)

CD=CM+MD=CA+DB

Từ (1), (2) suy ra góc COD=1/2*180=90 độ

c: AC*BD=CM*MD=OM^2=R^2

a: |x|=5,6

=>\(\left[{}\begin{matrix}x=5,6\\x=-5,6\end{matrix}\right.\)

c: \(\left|x\right|=3\dfrac{1}{5}\)

=>\(\left|x\right|=3,2\)

=>\(\left[{}\begin{matrix}x=3,2\\x=-3,2\end{matrix}\right.\)

d: |x|=-2,1

mà -2,1<0

nên \(x\in\varnothing\)

d: |x-3,5|=5

=>\(\left[{}\begin{matrix}x-3,5=5\\x-3,5=-5\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}x=8,5\\x=-1,5\end{matrix}\right.\)

e: \(\left|x+\dfrac{3}{4}\right|-\dfrac{1}{2}=0\)

=>\(\left|x+\dfrac{3}{4}\right|=\dfrac{1}{2}\)

=>\(\left[{}\begin{matrix}x+\dfrac{3}{4}=\dfrac{1}{2}\\x+\dfrac{3}{4}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{4}\\x=-\dfrac{5}{4}\end{matrix}\right.\)

f: \(\left|4x\right|-\left|-13,5\right|=\left|2\dfrac{1}{4}\right|\)

=>\(4\left|x\right|=2,25+13,5=15,75\)

=>\(\left|x\right|=\dfrac{63}{16}\)

=>\(x=\pm\dfrac{63}{16}\)

g: \(\dfrac{5}{6}-\left|2-x\right|=\dfrac{1}{3}\)

=>\(\dfrac{5}{6}-\left|x-2\right|=\dfrac{1}{3}\)

=>\(\left|x-2\right|=\dfrac{5}{6}-\dfrac{1}{3}=\dfrac{1}{2}\)

=>\(\left[{}\begin{matrix}x-2=\dfrac{1}{2}\\x-2=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{2}\\x=\dfrac{3}{2}\end{matrix}\right.\)

h: \(\left|x-\dfrac{2}{5}\right|+\dfrac{1}{2}=\dfrac{3}{4}\)

=>\(\left|x-\dfrac{2}{5}\right|=\dfrac{3}{4}-\dfrac{1}{2}=\dfrac{1}{4}\)

=>\(\left[{}\begin{matrix}x-\dfrac{2}{5}=\dfrac{1}{4}\\x-\dfrac{2}{5}=-\dfrac{1}{4}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{4}+\dfrac{2}{5}=\dfrac{13}{20}\\x=-\dfrac{1}{4}+\dfrac{2}{5}=\dfrac{-5+8}{20}=\dfrac{3}{20}\end{matrix}\right.\)

i: \(\left|5-3x\right|+\dfrac{2}{3}=\dfrac{1}{6}\)

=>\(\left|3x-5\right|=\dfrac{1}{6}-\dfrac{2}{3}=\dfrac{1}{6}-\dfrac{4}{6}=-\dfrac{3}{6}=-\dfrac{1}{2}< 0\)

=>\(x\in\varnothing\)

k: \(-2,5+\left|3x+5\right|=-1,5\)

=>|3x+5|=-1,5+2,5=1

=>\(\left[{}\begin{matrix}3x+5=1\\3x+5=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x=-4\\3x=-6\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}x=-\dfrac{4}{3}\\x=-2\end{matrix}\right.\)

m: \(\dfrac{1}{5}-\left|\dfrac{1}{5}-x\right|=\dfrac{1}{5}\)

=>\(\left|\dfrac{1}{5}-x\right|=\dfrac{1}{5}-\dfrac{1}{5}=0\)

=>\(\dfrac{1}{5}-x=0\)

=>\(x=\dfrac{1}{5}\)

n: \(-\dfrac{22}{15}x+\dfrac{1}{3}=\left|-\dfrac{2}{3}+\dfrac{1}{5}\right|\)

=>\(-\dfrac{22}{15}x+\dfrac{1}{3}=\dfrac{2}{3}-\dfrac{1}{5}\)

=>\(-\dfrac{22}{15}x=\dfrac{1}{3}-\dfrac{1}{5}=\dfrac{2}{15}\)

=>-22x=2

=>\(x=-\dfrac{1}{11}\)

1. English is more interesting than music.

2. Today they are not as happy as they were yesterday.

3. Ha Noi is not as small as Hai Duong.

4. Mai's sister is not as pretty as her.

6. You have got more money than me.

7. Art is not as difficult as French.

8. Nam's father is more careful than him.

9. No one in our town is as rich as Mr Ron.

10. He is the most intelligent in my class.

11. Everest is the highest mountain in the world.

12. Minh is the fattest person in my group.

13. I can't swim as far as Jan.

14B 15C 16A 17C 18B 19C 20B

bạn có thể chụp thẳng đc hong?????

a) Ta có: AB//CD.

=>ABH=BDC (2 góc so le trong).

=> ∆AHB~∆BCD(g.g).

b) ∆ABD có :  DB²=AB²+AD²( Định lý Pitago)

=> DB= 15(cm).

Ta có ∆ABH~∆BCD(cmt).

=>AH/BC=AD/BD.

Hay AH=9.12/15=7,2(cm).

c)Ta có ∆AHB~∆BCD cmt.

=> HBA=CBD. (1)

Ta lại có : CBD= ADH (AB//CD).(2)

Từ 1 và 2 => HAB=ADH.

=>∆DHA~∆AHB(g.g).

S∆DHA/S∆AHB=(AD/AB)²=9/16

d) từ câu (a) và (b) => ∆BCD~∆DHA.

Cm ∆DHA~∆MDA(g.g)

Từ đó  suy ra ∆BDC~∆MDA.

Sau đó cm ∆BCD~∆ADC(g.g).

=> ∆MDA~∆ADC(g.g).

=>Ad/DC=DM/DC.

=>Đpcm.