x/3=y/5=z/8 va 2x+y-z=12

=> x/3=y/5=z/8=2x/6= 2x+y-z/6+5-8=12/3=4

=> x=12   ;     y=20 ;     z= 32

Áp dụng tính chất dãy tỉ số bằng nhau ta có : 

\(\frac{x}{3}=\frac{y}{5}=\frac{y}{8}\)

\(\Rightarrow\frac{2x}{6}=\frac{y}{5}=\frac{z}{8}=\frac{2x+y-z}{6+5-8}=\frac{12}{3}=4\)

\(\Rightarrow\frac{x}{3}=4\Rightarrow x=12\)

\(\frac{y}{5}=4\Rightarrow y=20\)

\(\frac{z}{8}=4\Rightarrow z=32\)

ko chép lại đề

=3+16-1+8+9 9

=19-1+8+9 9

=18+8+9 9

=26+9 9

=26+81

107

nếu 3³ 3³ là dấu nhân thì nó sẽ như vậy

=3+16-1+8+27.27

=26+27*27

=755

Điền từ thích hợp 
 

Minh lives in a lovely apartment in Ho Chi Minh city. His apartment is  not very big but it is very comfortable .There are five rooms in the apartment : a living rooms , two bedrooms , a kitchen and a bathroom .  The  bathroom is very beatiful. It hass a sink, a tub and a shower. The kitchen is very kitchen is very modern. There are everything in the kitchen : refrigerator, washing machine, dishwasher , gas cooker , electric stove , oven , kitchen tablie , ..... Minh's bedroom isn't large , but it's very bright. There a  wonderful view from his bedroom. Minh really s his apartment very much.

 HỌC TỐT

1. They can’t make tea with cold water. 
- Tea can't be made with cold water. 

2 My sister started working for Ford company 10 years ago.

My sister has.......worked for Ford company for 10 years................................................................................

3. They have sold that old house.     That old house....has been sold by them....................................................................

4. She said: " I will come back here"

She said......she then she left here..............................................................................

6. They last visited that museum last year.

They haven't.....visited that museum for last year ..........................................................................

7. Learn hard and you will be successful.           If..you learn hard you will success........................................................

8. They worked hard so they passed the exam easily.

Because.....they worked hard , they passed the... exam easily............................................................................

học tốt

1. I want to be a footbal player 

2. She suggested to buy a new computer

3. We have been coresspond for over 2 years

4. America was discovered by C. Colombus in the 15th century

5. Minh hasn't seen her aunt since she moved to the city

hello????

\(|x-\frac{1}{3}|+\left|x-\frac{4}{3}\right|=\frac{9}{2}x\)

Ai nhanh nhất mik cho

Số thứ 8 là: 17 x 8 - 16 x 7 = 24

https://www.youtube.com/watch?v=6Enq4NkMyks&t=1213s

a) Xét ΔΔABH và ΔΔACH có:

AB = AC (gt)

A1ˆ=A2ˆA1^=A2^ (AH phân giác BACˆBAC^)

AH: chung

=> ΔΔABH = ΔΔACH (c.g.c)

=> {HB=HCAHBˆ=AHCˆ{HB=HCAHB^=AHC^ (ĐN 2 ΔΔ = nhau)

Vì H nằm giữa B, C (gt) và HB = HC (cmt)

=> H trung điểm BC (ĐN trung điểm)

Vì AHBˆ=AHCˆAHB^=AHC^ (cmt)

mà AHBˆ+AHCˆ=180oAHB^+AHC^=180o (2 góc kề bù)

=> AHBˆ=AHCˆ=90oAHB^=AHC^=90o

=> AH ⊥⊥ BC (ĐN 2 đường thẳng ⊥⊥)

b) Vì H trung điểm BC (cmt)

=> HB = HC = BC : 2 (t/c trung điểm) = 12 : 2 = 6cm

Xét ΔΔABH vuông tại H (AHBˆ=90oAHB^=90o) có:

AH2+HB2=AB2AH2+HB2=AB2 (ĐL Pi-ta-go)

=> AH2=AB2−HB2=102−62=64AH2=AB2−HB2=102−62=64

=> AH = 8cm

SABC=12BC⋅AH=12⋅12⋅8=48(cm2)

mk lm đc a,b rồi nha !!!