The length of a line is x centimetres.
Write down an expression, in terms of x, for the length of the line in millimetres.

Answers

Answer 1

Answer:

10x

Step-by-step explanation:

Since there are 10 mm in one cm, the expression would be 10x.

Hope this helps!

Answer 2

Answer:

10

Step-by-step explanation:

As we know that 1cm=10mm

so the expression would be 10x.


Related Questions

Solve for x. Round to the nearest tenth, if necessary.

Answers

Sin(theta) = opposite/hypotenuse

Sin(41 deg) = 2.5/x

Xsin(41) = 2.5

X = 2.5/sin(41)

X = 3.8

What is the final step in solving the inequality –2(5 – 4x) < 6x – 4? x < –3 x > –3 x < 3 x > 3

Answers

Answer:

x > 3

Step-by-step explanation:

Given the inequality :

-2(5 – 4x) < 6x – 4

Expand the equation in bracket :

-10 + 8x < 6x - 4

Collect like terms

-10 + 4 < 6x - 8x

-6 < - 2x

Divude both sides by - 2

-6 / - 2 < - 2x / - 2

3 < x

x > 3

Find the TWO integers whos product is -12 and whose sum is 1

Answers

Answer:

[tex] \rm Numbers = 4 \ and \ -3.[/tex]

Step-by-step explanation:

Given :-

The sum of two numbers is 1 .

The product of the nos . is 12 .

And we need to find out the numbers. So let us take ,

First number be x

Second number be 1-x .

According to first condition :-

[tex]\rm\implies 1st \ number * 2nd \ number= -12\\\\\rm\implies x(1-x)=-12\\\\\rm\implies x - x^2=-12\\\\\rm\implies x^2-x-12=0\\\\\rm\implies x^2-4x+3x-12=0\\\\\rm\implies x(x-4)+3(x-4)=0\\\\\rm\implies (x-4)(x+3)=0\\\\\rm\implies\boxed{\red{\rm x = 4 , -3 }}[/tex]

Hence the numbers are 4 and -3

Let integers be x and x-1

ATQ

x+x-1=1

[tex]\\ \sf\longmapsto 2x-1=1[/tex]

[tex]\\ \sf\longmapsto 2x=1+1[/tex]

[tex]\\ \sf\longmapsto 2x+2[/tex]

[tex]\\ \sf\longmapsto x=\dfrac{2}{2}[/tex]

[tex]\\ \sf\longmapsto x=1[/tex]

Now

[tex]\\ \sf\longmapsto x-1=1-1=0[/tex]

The integers are 1 and 0

But

Integers can be x and 1-x as their sum is 1

[tex]\\ \sf\longmapsto x(1-x)=-12[/tex]

[tex]\\ \sf\longmapsto x- x^2=-12[/tex]

[tex]\\ \sf\longmapsto x^2-x-12=0[/tex]

[tex]\\ \sf\longmapsto x^2-4x+3x-12=0[/tex]

[tex]\\ \sf\longmapsto x(x-4)+3(x-4)=0[/tex]

[tex]\\ \sf\longmapsto (x-4)(x+3)=0[/tex]

[tex]\\ \sf\longmapsto x=4,-3[/tex]

What percentage of 1hour is 6munites 20seconds

Answers

Answer:

10

Step-by-step explanation:

10 percentage for this question answer

Pam laid three times as many tiles on Saturday as she laid on Sunday. If Pam laid 80 tiles over the weekend altogether, how many tiles did she lay on Saturday?

Answers

Answer:

Pam laid 60 tiles on Saturday and 20 on Sunday.

Step-by-step explanation:

Given that Pam laid three times as many tiles on Saturday as she laid on Sunday, if Pam laid 80 tiles over the weekend altogether, to determine how many tiles did she lay on Saturday the following calculation must be performed:

3X + X = 80

4X = 80

X = 80/4

X = 20

Therefore, Pam laid 60 tiles on Saturday and 20 on Sunday.

Find the length of side AB.
Give your answer to 1 decimal place.
12 cm
62°
A
B

Answers

Hey there!

To solve this problem, we will be using Trigonometric Ratio. Trigonometry is always helpful when it comes to finding a missing side with specific measure/angle.

1. Cosine Ratio

Currently, there are 6 Trigonometric Ratios. But we will be talking about Cosine Ratio instead since it is what we will be using in your question! Cosine Ratio is defined as adjacent to hypotenuse or adjacent/hypotenuse. You know what adjacent and hypotenuse are right? If not then head to the next topic!

2. Adjacent and Hypotenuse

Adjacent is basically the base of a triangle. It is basically drawn from right angle to any measure/angles. Hypotenuse is the longest side of a right triangle. It is also an opposite side of right angle.

Hope you understand this topic! If not, feel free to ask!

3. Solve The Problem

Since our adjacent is length AB but we don't know its exact value. What we have to do is to determine AB as any variables which I will determine AB as "x". Next, we have the value of hypotenuse which is 12 cm. Then we also know the Cosine Ratio which is adjacent to hypotenuse.

Therefore, the equation for the problem is:

[tex] \large{cos62 \degree = \frac{x}{12} }[/tex]

*cos is the short form of cosine*

At this part, we need a calculator to find the value of cos62 degrees. That's because it is not a degree like 0, 30, 45, 60 and 90 which can be found without a calculator.

When we put cos62 in a calculator, make sure to put it in degree mode since a calculator has two modes which are degree and radian.

When we put cos62 in, we should get 0.46947156... Because you want a one decimal place, we round the value up to the nearest tenth as we get 0.5 because 6 is greater than 5 and should be rounded up and not down. That makes the equation to:

[tex] \large{0.5 = \frac{x}{12} }[/tex]

Oh well! Finally to the equation part. Whenever you have to solve the equation that has decimal numbers in it, the best way to deal with decimal numbers is to make them into a whole number or integer. But how? Simply multiply the whole equation by 10. Because 0.5×10 is 5 thus 0.5 becomes an integer after multiplying 10.

[tex] \large{0.5 \times 10 = \frac{x}{12} \times 10} \\ \large{5 = \frac{10x}{12} }[/tex]

10x/12 can be simplified again.

[tex] \large{5 = \frac{5x}{6} }[/tex]

Then we isolate x-value by multiplying 6 the whole equation.

[tex] \large{5 \times 6 = \frac{5x}{6} \times 6} \\ \large{30 = 5x} \\ \large{x = 6}[/tex]

Huh, that's awkward! We want the answer in a 1 decimal place but seems like the answer for this is 6. Why? Well that is not an exact answer, but more like an approximation. Because the value of cos62 degree is actually a repeating decimal and doesn't have exact value.

When we put the equation cos62 = x/12 in the equation and solve. It appears that the the answer is 5.63365875. Because we round up to nearest tenth, it gives an approximation to 5.63365875 instead.

Hence, the equation and value above is just a rounded to the whole number from 5.63365875.

Because you want a one place decimal. Hence,

4. Final Answer

The length AB is 5.6 (rounded to nearest tenth)

pada hari kantin sebanyak 800 naskah kupon telah dijual,harga senaskah kupon masing masing rm 30 dan rm 50 .jumlah wang diperoleh hasil daripada jualan kupon ialah rm30000.berapa naskah kupon rm30 dan rm50 yang telah dijual?

Answers

Answer:

Step-by-step explanation:

On the day of the canteen, 800 coupons were sold, the price of each coupon was RM 30 and RM 50 respectively. The amount of money earned from the sale of coupons was RM30000. How many copies of RM30 and RM50 coupons were sold?

Let:

RM 30 = x

RM 50 = y

x + y = 800 - - - (1)

30x + 50y = 30000 - - - (2)

From (1)

x = 800 - y

Put x = 800 - y in (2)

30(800 - y) + 50y = 30000

24000 - 30y + 50y = 30000

24000 + 20y = 30000

20y = 30000 - 24000

20y = 6000

y =

Find the area of the triangle whose vertices are (2, 3); (-1, 0); (2, -4)...
[Also show the steps of the solution]
Please answer correctly, it's really urgent!​

Answers

Answer:

Area = 14.5

Step-by-step explanation:

Let's label the given coordinates A, B, C;

Thus;

A = (2, 3)

B = (-1, 0)

C = (2, -4)

From the coordinate geometry formula, the formula for area of a triangle with 3 vertices is;

Area = [Ax(By - Cy) + Bx(Cy - Ay) + Cx(Ay - By)]/2

Area = [2(0 - (-4)) + (-1)(-4 - 3) + 2(3 - (-4))]/2

Area = 29/2

Area = 14.5

A stereo was originally priced at 75.50. it was marked down 24%. a store had a big sale of 60% off the lowest marked price. what was the final price of the stereo

Answers

Answer:

We can calculate the price with both  sales by multiplying the 75.5 units of money by both percentages (to multiply them, we divide them by 100 first):

75.5 * 0.24 * 0.6 [tex]\approx.[/tex] 10.8

PLEASE ANSWER CORRECTLY FOR BRAINLIEST:

25.

26.

27.

29.

Answers

Answer:

x = 6

Step-by-step explanation:

5 (x - 3) + 2 = 5 (2x - 8) - 3

remove the parenteses

5x - 15 + 2 = 10x - 40 - 3

calculate

5x - 13 = 10x - 43

move the terms

5x - 10x = -43 + 13

collect like terms calculate

-5x = -30

divide both sides

Solution

x = 6

help me. what is the answer. what is the equation of the line shown?

Answers

peepee !!!! LOL pee pee

Solve the following linear quadratic system of equations algebraically.

y=^2+3x-2
y+3=5x

Answers

Answer:

[tex]x=1[/tex]

[tex]y=2[/tex]

Step-by-step explanation:

[tex]y=x^2+3x-2[/tex] , [tex]y+3=5x[/tex]

Replace all occurrences of [tex]y[/tex] in [tex]y+3=5x[/tex] with [tex]x^2+3x-2.[/tex]

[tex](x^2+3x-2)+3=5x[/tex]

[tex]y=x^2+3x-2[/tex]

Add [tex]-2[/tex] and 3.

[tex]x^2+3x+1=5x[/tex]

[tex]y=x^2+3x-2[/tex]

Subtract 5x from both sides of the equation.

[tex]x^2+3x+1-5x=0[/tex]

[tex]y=x^2+3x-2[/tex]

Subtract 5x from 3x.

[tex]x^2-2x+1=0[/tex]

[tex]y=x^2+3x-2[/tex]

Rewrite 1 as [tex]1^2[/tex].

[tex]x^2-2x+1^2=0[/tex]

[tex]y=x^2+3x-2[/tex]

Check that the middle term is two times the product of the numbers being squared in the first term and third term.

[tex]2x=2[/tex] · [tex]x[/tex] · [tex]1[/tex]

[tex]y=x^2+3x-2[/tex]

Rewrite the polynomial.

[tex]x^2-2[/tex] · [tex]x[/tex] · [tex]1[/tex] [tex]+[/tex] [tex]1^2=0[/tex]

[tex]y=x^2+3x-2[/tex]

Factor using the perfect square

trinomial rule [tex]a^2-2ab+b^2=(a-b)^2,[/tex]

where a = x and b = 1.

[tex](x-1)^2=0[/tex]

[tex]y=x^2+3x-2[/tex]

Set the [tex]x-1[/tex] equal to 0.

[tex]x-1=0[/tex]

[tex]y=x^2+3x-2[/tex]

Add 1 to both sides of the equation.

[tex]x=1[/tex]

[tex]y=x^2+3x-2[/tex]

Replace all occurrences of [tex]x[/tex] in

[tex]y=x^2+3x-2[/tex] with 1.

[tex]y=(1)^2+3(1)-2[/tex]

[tex]x=1[/tex]

[tex]y=2[/tex]

find the value of x to the nearest tenth

Answers

7

Step-by-step explanation:

To solve this you need to use trigonometry:

1. Identify the sides. In this case, x is opposite and 10 is adjacent.

2. Identify which part of SOHCAHTOA you need to use. In this case, you need to use TOA.

3. Form your equation. In this case, x = tany x A

4. Substitute numbers into your equation. In this case, x = tan35° x 10

5. Calculate this equation using a scientific calculator. In this case the answer is 7.

Simplify the expression. x^4/ x^7
a x-11
b x-3
c x11
b x3

Answers

Answer:

b

Step-by-step explanation:

[tex]\frac{x^4}{x^7} =x^4 \times x^{-7} =x^{4-7} =x^{-3}[/tex]

A water storage tank has the shape of a cylinder with diameter 14 ft. It is mounted so that the circular cross-sections are vertical. If the depth of the water is 12 ft, what percentage of the total capacity is being used

Answers

Answer:

"85.7%" is the right answer.

Step-by-step explanation:

According to the question,

The total capacity of water tank will be:

⇒ [tex]v_1=A\times 14[/tex]

The total volume of water will be:

⇒ [tex]v_2=A\times 12[/tex]

Now,

The percentage of total capacity will be:

= [tex]\frac{100\times v_2}{v_1}[/tex]

= [tex]\frac{v_2}{v_1}\times 100[/tex]

By putting the values, we get

= [tex]\frac{A\times 12}{A\times 14}\times 100[/tex]

= [tex]85.7[/tex]%

PLS HELP ASAP
WHICH IS THE RIGHT ASNWER OF THE FUNCTION PICTURED BELOW? A,B,C,D?

Answers

Answer:

Step-by-step explanation:

C looks right

as shown in the graphs  :P

express 3 as a percent of 5

Answers

Answer:

0.15

Step-by-step explanation:

first get three percent:

3/100 = 3%

then use of operation:

3% of 5;

= (3/100) * 5

Answer:

60%

Step-by-step explanation:

To change a fraction to a percentage, multiply the fraction by 100% , then

[tex]\frac{3}{5}[/tex] × 100% = [tex]\frac{3(100)}{5}[/tex] = [tex]\frac{300}{5}[/tex] = 60%

Problem 2. Joe has 7 shirts 4 pairs of pants and 2 pairs of shoes.He needs to make an outfit containing one of each item.How many different outfits are possible?

Answers

Answer:

56 different outfits

Step-by-step explanation:

Your plane leaves Boston (Eastern Standard Time) at 7:00am, bound for Los Angeles (Pacific Standard Time). The flight takes 5 hours. What is time when you arrive in Los Angeles

Answers

Answer:

The plane arrives Los Angeles at 9:00 am

Step-by-step explanation:

The Pacific Standard Time (PST) in Los Angeles is 3 hours earlier than the Eastern Standard Time (EST) in Boston

Therefore,

7:00 am at Boston = 4:00 am in Los Angeles

If the plane takes 5 hours

What is time when you arrive in Los Angeles

The plane arrives Los Angeles at 4:00 am + 5:00 hours

= 9:00 am

The plane arrives Los Angeles at 9:00 am

PLS HELP ILL GIVE U BRAINLIEST HURRY!!!!!!!

Answers

I remember doing g that back in high school. Sorry but I can’t see the numbers too well

How would the domain and range of the function y = one-fourth x minus 6 be determined? Explain.

Answers

Answer:

Domain = ( -∞ , ∞ )

Range = ( ∞ , ∞ )

Step-by-step explanation:

A function is given to us and we need to find the domain and range of the given function .

The function :-

[tex]\rm \implies y = \dfrac{1}{4}x - 6 [/tex]

Definitions :-

Range :- The range is the set of all valid y values .Domain :- All real numbers except where the expression is undefined.

In this case, there is no real number that makes the expression undefined. Therefore the domain will be :-

Domain :-

[tex]\rm Domain = ( -\infty , \infty ) [/tex]

or

[tex]\rm Domain = \{ x | x \in \mathbb{R} \}[/tex]

Range :-

[tex]\rm Range = ( -\infty , \infty ) [/tex]

or

[tex]\rm Range = \{ y | y \in \mathbb{R}\} [/tex]

Answer:

Create a table or a graph of the function. The domain represents all input values and the range represents all output values. The domain and range contain all real numbers.

Step-by-step explanation:

- (For 10 points!)

Alfred draws candles randomly from a pack containing 4 colored candles of the same shape and size. There are 2 red candles, 1 green candle, and 1 blue candle. He draws 1 candle and then draws another candle without replacing the first one. Find the probability of picking 1 red candle followed by another red candle, and show the equation used.

(don't joke around please?? /gen)

Answers

Answer:

The probability of picking 1 red candle followed by another red candle is 16.66%.

Step-by-step explanation:

Since Alfred draws candles randomly from a pack containing 4 colored candles of the same shape and size, and there are 2 red candles, 1 green candle, and 1 blue candle, and he draws 1 candle and then draws another candle without replacing the first one, to find the probability of picking 1 red candle followed by another red candle, the following calculation must be performed:

2/4 x 1/3 = X

0.5 x 0.333 = X

0.16666 = X

Therefore, the probability of picking 1 red candle followed by another red candle is 16.66%.

Answer:

1/6

Step-by-step explanation:

2/4 x 1/3 = 1/6

y=x+2 y=-x +8 What is the solution for this system of equations?​

Answers

Answer:

x = 3     y = 5

Step-by-step explanation:

     y=x+2

+    y=-x +8

2y = 10

y = 5

y = -x + 8

5 = -x + 8

x = 3

What is the length of the unknown leg in the right triangle…?

Answers

As we know,

In a triangle, the sum of lengths of two side is greater than the third side.

[tex]20 + 25 > b[/tex]

[tex]b + 20 > 25[/tex]

[tex]25 + b > 20[/tex]

Answer = 15m

Cláudio pode ir de sua casa a escola andando três km para o Norte, 2 para o oeste, um para o sul, quatro para o leste e, finalmente, 2 para o sul ponto para ir de sua casa a escola em linha reta, Cláudio deve andar: a) 1 km para o sul b) 2 Km para o leste c) 3 km para o oeste d) 4 km para o Norte e) 5 km para o leste

Answers

Answer:

b) 2 Km para o leste

Step-by-step explanation:

1. 2 km N

2. 2 km W

3. 1 km S

4. 4 km E

5. 2 km S

Sul e Norte:

(1.) 2 km N + (3.) 1 km S + (5.) 2 km S = 2 km - 1 km - 2 km = 0

Este e Oeste:

(2.) 2 km W + (4.) 4 km E = -2 km + 4 km = 2 km E

Veja imagem abaixo.

In 90 minutes, John can run 30 laps around the track. Determine the number of laps he can run per hour.

Answers

Answer:

in 90 minutes he ran 30 laps

there is 60 minutes in a hour so the fraction would be

2/3 so we have to multiply this by 30

2/3*30=20

He can run 20 laps in a hour

Hope This Helps!!!

WILL MARK AS BRAINLIEST. PLS HLP MEEE​

Answers

I’m confused what are u trying to am skmdi
Uhm I think it’s 21 because I don’t know the answer well

they help me ? is the last someone please

Answers

The 3rd one because the integer is greater then or equal 0

2. Resolve into factors.
a) 8x3 + y3​

Answers

Answer:

(2x + y)(4x² - 2xy + y²)

Step-by-step explanation:

8x³ + y³ ← is a sum of cubes and factors in general as

a³ + b³ = (a + b)(a² - ab + b²) , then

8x³ + y³

= (2x)³ + y³

= (2x + y)((2x)² - 2xy + y²) , that is

(2x + y)(4x² - 2xy + y²)


Rab has trouble remembering the difference between addition of a positive and
negative number and multiplication of a positive and negative number. Explain how
you could clarify the concepts for him. Use an example to back up your explanation.

Answers

Addition of a positive and negative number always means that you are going to subtract the number e. g. 4+-1 = 3. However, multiplication of a positive and negative number means the answer is always negative e. g. 5 x - 3 = - 15.

The addition of positive and negative number will always subtract with sign of maximum value.

The multiplication of positive and negative number will have a negative sign always.

AdditionConcept for the addition of positive and negative number

When two numbers which have different sign are added, they will always be subtracted from each other. The sign will vary accordingly.

with negative sign: when two numbers are added such that the number with negative sign has the larger value, then both numbers will get subtracted but with negative sign.

Example: Consider two number -5 and 4

= -5 + 4

= -1

Here, 5 is the larger value. So, the sign comes is negative.

with positive sign: when two numbers are added such that the number with positive sign has the larger value, then both numbers will get subtracted but  with positive sign.

Example: consider two number 5 and -4.

= 5 + (-4)

= 1

Here, 5 is the large number. So, the sign comes is positive.

MultiplicationConcept for the multiplication of positive and negative number:

When two numbers with opposite signs are multiplied, the answer is always a negative number.

Example; Consider two numbers 4 and -5.

On multiplication,

4×(-5) = -20

Thus, the multiplication of two numbers with different signs will always give a negative number.

To know more about rational and irrational numbers, here

https://brainly.com/question/5796983

#SPJ2

Other Questions
Marcia, Maureen, and Mario want to buy a $132 present for Sarah. Maureen is paying one half of Marcia's quantity, and Mario, one third of Marcia's quantity. Luckily for them the item has an 18% discountHow much is Mario paying? Zoe walks at a speed of 10 miles/h and jogs at a speed of 20 miles/h. She goes to the park to walk 2 miles on a Monday. How long will she take to walk 2 miles? Can someone please give me a clear definition of what ceramics are? It will really help! :) Have u ever help caste people or language people or who dont have eye? wirte in paragraph Who is Nat King Cole???Pls answer ASAP!!!30 pts Hai gi sch c 450 cun sch .Nu chuyn 50 quyn t gi th nht sang gi th hai th s sch gi s hai s bng 4/5 s sch gi th nht ?Tnh s sch mi gi. please help ill mark brainliest ILL MAKE U BRAINIESTWhich of the following is NOT a question you need to ask when identifying a photograph as a reliable source?O A. Why was this photograph taken?OB. Was the photograph captured on film or a digital camera?C. Who is the photographer and how are they connected to the event?D. Is there any way this photograph could have been staged? How do sections work together to build an informational article as a whole?They can engage the reader with new information.They can be used to contrast ideas in a different text.They can answer cause and effect questionsThey can provide explanation and examples. Armando planted a 9-inch tall magical beanstalk. The height of the beanstalk increases by 13% each day. Write a function f that determines the height of the beanstalk in inches in terms of the number of days t since Armando planted the beanstalk. PLEASE HELP!! What is the effect of the word choice in the phrase when you are set down at random in that street in the middle of an inky black night in Paragraph 2 of the passage?A. It gives the paragraph a humorous tone.B. It contrasts the description of the Mississippi River.C. It creates a strong, relatable image.D. It sets a dark, ominous mood.The passage: One cannot easily realize what a tremendous thing it is to know every trivial detail of twelve hundred miles of river and know it with absolute exactness. If you will take the longest street in New York and travel up and down it, conning its features patiently until you know every house and window and lamppost and big and little sign by heart, and know them so accurately that you can instantly name the one you are abreast of when you are set down at random in that street in the middle of an inky black night, you will then have a tolerable notion of the amount and the exactness of a pilot's knowledge who carries the Mississippi River in his head. Alex has collected apples. It has 40 boxes of 8.5 kg each and 6 sacks of 90kg each. Pack the apples in bags of 2.5 kg each. how many bags do you get? 8w + 19 - 4w = -5? What is the value of w? The train .......... (will have left/ will leave) from Rajkotby 10 PM 2. A computer that is easy to operate is calledI10 POINTSSSS PLEASEEE HELPPP DIT QUESTION what is the theme of brown girl dreaming While Mr. Yoo was painting the bedroom, Mr. Kerr _____ furniture from the living room. Lee is in customer service. How can she best support her internal customer, Dan? O al Prioritize other tasks and customers O b) Ask him a lot of personal questions O c) Give him her full attention when he's speaking O d) Check with him before completing basic tasks 3. Ngy 01/01/N, Cng ty F nhn c mt thng phiu do cng ty A pht hnh vi mnh gi X (Sinh vin t cho s liu ca X > 100.000$), li sut 11%, thi hn 5 nm, li c tr nh k vo cui nm. Li sut th trng cho thng phiu tng t l 15%/nm. (2,5 im)Yu cu1. Anh (ch) hy xc nh gi tr hin ti (gi pht hnh) ca thng phiu? Chit khu (Ph tri) thng phiu? nh khon ghi nhn thng phiu phi thu ti ngy pht hnh i vi cng ty F v nh khon ghi nhn thng phiu phi tr ti ngy pht hnh i vi cng ty A? Cho nhn xt ca anh ch.2. Lp bng phn b gi tr chit khu (ph tri) thng phiu theo phng php li thc? nh khon ghi nhn doanh thu li cui nm u tin i vi cng ty F; chi ph li cui nm u tin i vi cng ty A.3. Thc hin yu cu 1 v yu cu 2 nu li sut th trng cho thng phiu tng t l 9%/nm.Bit rng TABLE 6-4 PRESENT VALUE OF AN ORDINARY ANNUITY OF 1: Bng 6-4: Bng tra tnh ton gi tr hin ti ca li thng phiuTABLE 6-2 PRESENT VALUE OF 1: Bng 6-2: Bng tra tnh ton gi tr hin ti ca gc thng phiu nh nc u tin vit nam?