11C

12D

13B

14A

15 thiếu hình

16B

Trắc nghiệm
Câu 1:B

Câu 2:C

Câu 3:A

Câu 4:C

Câu 5:A 

Câu 6:B

Câu 7:D

Câu 8:D

a: BC=căn 6^2+8^2=10cm

AM=BC/2=5cm

b:

ΔAEH vuông tại A có AI là trung tuyến

nên IH=IA

=>góc IHA=góc IAH

góc IAH+góc MAB

=góc MBA+góc IHA=90 độ

=>góc IAM=90 độ

=>AI vuông góc AM

a: Ta có: \(\sqrt{x^2-4x+4}=\sqrt{4x^2-12x+9}\)

\(\Leftrightarrow\left|x-2\right|=\left|2x-3\right|\)

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

c: Ta có: \(\sqrt{4x^2-4x+1}=\sqrt{x^2-6x+9}\)

\(\Leftrightarrow\left|2x-1\right|=\left|x-3\right|\)

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

was thought that the house was broken into last night. 

house was thought to have been broken into last night. 

hotel regulations should be read carefully by the hotel guests. 

languages are spoken in Canada? 

bike was left in the hall this morning.

2:

a: BC=căn 15^2+20^2=25cm

AH=15*20/25=12cm

góc ADH=góc AEH=góc DAE=90 độ

=>ADHE là hình chữ nhật

=>DE=AH=12cm

b: ΔAHB vuông tại H có HD vuông góc AB

nên AD*AB=AH^2

ΔAHC vuông tại H có HE vuông góc AC

nên AE*AC=AH^2

=>AD*AB=AE*AC

c: góc IAC+góc AED

=góc ICA+góc AHD

=góc ACB+góc ABC=90 độ

=>AI vuông góc ED

4:

a: góc BDH=góc BEH=góc DBE=90 độ

=>BDHE là hình chữ nhật

b: BDHE là hình chữ nhật

=>góc BED=góc BHD=góc A

Xét ΔBED và ΔBAC có 

góc BED=góc A

góc EBD chung

=>ΔBED đồng dạng với ΔBAC
=>BE/BA=BD/BC

=>BE*BC=BA*BD

c: góc MBC+góc BED

=góc C+góc BHD

=góc C+góc A=90 độ

=>BM vuông góc ED

Em cần giúp câu nào hả em? Em nên chụp 1-2 ý cho 1 lần hỏi nhá, như thế mọi người sẽ dễ dàng giúp em hơn

13

a, \(3x-4=-x+8\)

\(< =>3x+x=8+4\)

\(< =>4x=12\)

\(< =>x=\frac{12}{4}=3\)

b, \(\frac{2x+1}{6}+\frac{x-7}{12}=10\)

\(< =>\frac{2\left(2x+1\right)}{12}+\frac{x-7}{12}=\frac{120}{12}\)

\(< =>4x+2+x-7=120\)

\(< =>5x=120+5=125\)

\(< =>x=\frac{125}{5}=\frac{5^3}{5}=5^2=25\)

13

c,\(\left(x+1\right)^2-\left(x-1\right)^2=12\)

\(< =>x^2+2x+1-x^2+2x-1=12\)

\(< =>4x=12< =>x=\frac{12}{4}=3\)

d,\(3\left(x-1\right)< x+5\)

\(< =>3x-3< x+5\)

\(< =>3x-x< 5+3=8\)

\(< =>x< \frac{8}{2}=4\)

2. It is thought that he stole the money.

He is thought to have stolen the money.

3. It is said that she is going to study abroad.

She is said to be going to study abroad.

4. It is thought that the house was broken into last night.

The house was thought to be broken into last night.

1............to work by car everyday

2 ........Khanh does morning exercise, he won't keep fit

3......has a small garden

4 .....has to go to school on time

5 ......she doesn't go to bed early, she will be late for class

6 .......go to the movie tonight

\(\text{⩷!⨙┏⇴⨗⨜}\)