Nêu định nghĩa số hữu tỉ? Nêu quy tắc cộng, trừ, nhân ,chia số hữu tỉ?

Answers

Answer 1

số hữu tỉ là các số x có thể biểu diễn dưới dạng phân số [tex]\frac{a}{b}[/tex]  trong đó a và b là các số nguyên với b {\displaystyle \neq }\neq  0.[1] Tập hợp số hữu tỉ ký hiệu là {\displaystyle \mathbb {Q} }{\displaystyle \mathbb {Q} }.[2]

Step-by-step explanat

ion:

Answer 2

Answer:

Step-by-step explanation:

Nu Nh Ngha S Hu T? Nu Quy Tc Cng, Tr, Nhn ,chia S Hu T?
Nu Nh Ngha S Hu T? Nu Quy Tc Cng, Tr, Nhn ,chia S Hu T?
Nu Nh Ngha S Hu T? Nu Quy Tc Cng, Tr, Nhn ,chia S Hu T?

Related Questions

Find the surface area of each figure. Round your answers to the nearest tenth, if necessary​

Answers

Answer: 109m^2

Step-by-step explanation:

(5)(8.4)/2 = 21 m^2

(4 ) (21) = 84 m^2

Base = 5^2 = 25 m^2

84 + 25 = 109 m^2

What is equivalent to 1/6

Answers

Answer:

0.16666...

6/36

2/12

3/18

4/24

5/30

There's a lot of things.

A Triangular Park ABC has sides 120 m, 80m and 50m. a gardener has to put a fence all around it and also plant grass inside. How much area does she need to plant? Find the cost of fencing it with barbed wire at the rate of of Rs. 20 per metre leaving a space 3m wide for a gate on one side?​

Answers

The perimeter = sum of all sides

= 120 + 80 + 50

= 250

So 250 - 3

247

Left space for gate

Now cost of fencing = Rs 20/per meter

= 247 × 20

= Rs 4,940

Now the area of the triangular park can be found using heron's formula

S = (a+b+c)/2

S = (120+80+50)/2

S = 250/2

S = 125

Now

Herons formula = √s(s-a)(s-b)(s-c)

√125(125-120)(125-80)(120-50)

√125(5)(45)(70)

√5×5×5×5×5×3×3×5×14

After Making pairs

5×5×5×3√14

375√14

Therefore 375√14m is the area of the triangular park

Must click thanks and mark brainliest

$\sf\underline\bold{Answer:}$

$\sf\small\underline{\underline{Area\: planted\: by\: the\: gardener : 1452.36m^2}}$

$\sf\small\underline{\underline{The\:cost\:of\:fencing\:the\:park:Rs.4940}}$

$\space$

$\sf\underline\bold{Step-by-Step:}$

$\space$

$\sf\bold{Given(In \:the\:Q):}$

Sides of the triangular park are 120m,80m and 50m.

$\space$

$\sf\bold{To \: find:}$

How much area of the park does she need to plant?The cost of fencing the park ?

$\space$

$\sf\small{☆Area\:to\:be\:planted=Area \: of \: ∆ABC}$

$\space$

$\sf\underline\bold{Calculating\:area\:of\:∆ABC:}$

$\space$

Use heron's formula to find the area of the triangle.

$\space$

$\mapsto$ $\sf\small{Heron's\:formula=}$

[tex]\sf\sqrt{s(s-a)(s-b)(s-c)}[/tex]

$\sf{Where\:s=semi\:perimeter}$$\sf{a,b,c\: = side\:of\:the\:∆}$$\sf\small{Here\:a=120,b=80 \:and\: c=50}$

$\space$

$\sf\bold{Now,find\:semi\:parameter:-}$

$\sf\small{Perimeter\:of\:the\:∆=120+80+50=250}$

$\sf\small{Semi-Perimeter:}$ $\sf\dfrac{250}{2}$ $\sf\small{=125m}$

$\space$

$\sf\small{Substitute \: the\:values\:in\:heron's\:formula:}$

$\sf{Area\:of\:the\:∆:-}$

$\mapsto$ [tex]\sf\sqrt{125(125-120)(125-80)(125-50)}[/tex]

$\space$

$\mapsto$ $\sf\sqrt{125\times(5)\times(45)\times(75)}$

$\space$

$\mapsto$ $\sf\small\sqrt{2109375}$ $\sf\small{=375}$ $\sf\small\sqrt{15}$

$\space$

$\longmapsto$ $\sf\underline\bold\purple{1452.56m^2}$

______________________________

$\sf\underline\bold{Now,find\:the\:cost\:of\:fencing:}$

$\sf{Cost\:of\:fencing-}$

$\sf{Rate = Rs.20 per \:meter}$ $\sf{Left\:space=3m}$

$\space$

$\sf\underline{Hence,the\:gardener\:has\:to\:fence:}$

$\sf{= 250-3=247m.}$

$\space$

So,total cost of fencing at the rate of Rs.20 per m:-

$\sf\underline\bold\purple{=247\times20=4940}$

___________________________________

pls look at the image and solve all.​

Answers

Answer:

Solution of question number 23

Step-by-step explanation:

Given,

5a - 12

= 5 × 12

= 15 - 12

= 3 answer

The equation of a line is y = 2x + 3. What is the equation of the line that is parallel to the first line and passes through (2, –1)?
A.
4x – 2y = –6
B.
y = 2x – 5
C.
y = 3x + 4
D.
2x + y = –1

Answers

Answer:

i think the answer is y = 3x + 4

Step-by-step explanation:

:)

Two standard dice are rolled together. What is the probability of rolling a sum less than 7 or a sum divisible by 5?

Answers

Answer:

Sum less than: 7 (1,1), (1,2), (1,3), (1,4), (1,5), (2,1), (2,2), (2,3), (2,4), (2,5), (3,1), (3,2), (3,3), (3,4), (3,5), (,4,1), (4,2), & (5,1)

Sum divisible by 5 (1,4), (2,3), (3,2), (4,1)

the tub started with gallons of water

Answers

Answer:

huh?

Step-by-step explanation:

(8-16) + (8 + 6)
If the parentheses are removed from the above
expression, how will the value of the expression
change?
A. no change
B. increase of 3
C. increase of 7
D. increase of 12
E. increase of 16

Answers

Step-by-step explanation:

Right now, we would solve everything within the parenthesis first.

(8 - 16) + (8 + 6)

(-8) + (14)

14 - 8

6

But if we remove the parenthesis, it doesn't matter what order we do things in.

8 - 16 + 8 + 6

8 + 8 - 16 + 6

16 - 16 + 6

6

The reason why both of these are the same, is because the only calculations we're doing are addition and subtraction, which don't care about parenthesis.

Answer:

A

The answer is A. The only calculations were doing here are addition and subtraction and it doesn’t matter what order u do them in. If there was any multiplying or division here it would be different. The answer is A. Also can I get brainliest please?

A survey found that 8 out of 10 parents approved of the new principal’s performance. If 4 parents name are chosen with replacement what is the probability they all approve of the principal’s performance

Answers

Answer:

The probability is 0.044

Step-by-step explanation:

Step-by-step explanation:

Let p be the probability that the new principal’s performance is approved.

This is obtainable from the survey and it is 8/10 = 0.8

Let q be the probability that the new principal’s performance is disproved.

That will be;

1 - q = 1- 0.8 = 0.2

To calculate the probability that 14 parents names are chosen at random and they all

approve of the principal’s performance, we use the Bernoulli approximation of the binomial theorem.

That will be;

14C14 * p^14 * q^0

= 1 * 0.8^14 * 0.2^0

= 0.043980465111 which is approximately 0.044

inverse sine is used to find a given angle measure when we know the _ and the _​

Answers

Answer:

opposite side of an angle

hypotenuse

how do i know when an equation has 1 solution

Answers

Answer:

you can plug it back into the original equation to see if it fits the solution. if not then you have another solution you need to solve for.

Answer:

if we're talking on linear equations, then the two equations would intersect at one point. or when you solve it, it'll be only 1 number that can fit that equation.

p.s.: sub to #gauthmath# sub reddit if ya can ^^

Element X is a radioactive isotope such that every 42 years, its mass decreases by
half. Given that the initial mass of a sample of Element X is 50 grams, how long
would it be until the mass of the sample reached 45 grams, to the nearest tenth of a
year?

Answers

Answer:

6.38548 years

Step-by-step explanation:

1 = 2 [tex]e^{42k}[/tex]

1/2 =   [tex]e^{42k}[/tex]

ln(1/2) = 42k ln(e)

ln(1/2)/42 = k

k = -0.01650

~~~~~~~~~~~~~~

45 = 50 [tex]e^{-0.01650t}[/tex]

45/50 =   [tex]e^{-0.01650t}[/tex]

ln(45/50) =  -0.01650 t ln(e)

ln(45/50)/ -0.01650 = t

t = 6.38548 years

The number of years for the radioactive element to reach a mass of 45 grams is given by t = 6.384129 years

What is half-life of an element?

The half-life of a radioactive isotope is the amount of time it takes for one-half of the radioactive isotope to decay. The half-life of a specific radioactive isotope is constant; it is unaffected by conditions and is independent of the initial amount of that isotope.

Half-life (symbol t½) is the time required for a quantity (of substance) to reduce to half of its initial value

The decay constant λ is = 0.693/t½

where t½ is the half-life of the element

Given data ,

Let the number of years be t

Let the initial mass of the element be a = 50 grams

The final mass of the element be ( a - x ) = 45 grams

Now , Element X is a radioactive isotope such that every 42 years, its mass decreases by half

And , half life t½ = 42 years

So , the decay constant k = 0.693/t½

k = 0.693 / ( 42 )

k = 0.0165

And , k= 2.303/t {log (a/a-x)}

So , t = 2.303 / ( 0.0165 ) log ( 50/45 )

On simplifying , we get

t = 6.384129 years

Hence , the number of years for the radioactive element to reach 45 grams is 6.384129 years

To learn more about half-life of an element click :

https://brainly.com/question/16387602

#SPJ2

Find the value of n. A. 10 B. 6 C. 50 D. 25

Answers

I’m thinking the answer would be D

find the measure of the indicated angle to the nearest degree​

Answers

Answer:

28°

Step-by-step explanation:

sin ? = 19/41

? = arcsin (19/41)

? = 28° (rounded to the nearest degree)

Answered by GAUTHMATH

A rectangle with an area of 3990 cm2 is x centimeters wide and (x+4) centimeters long. To the nearest tenth of a centimeter, the width and length are

Answers

Answer: width:60.2 cm

Length: 64.2 cm

Step-by-step explanation:

Given

The area of the rectangle is [tex]3990\ cm^2[/tex]

Width of the rectangle is [tex]x\ cm[/tex]

Length of the rectangle is [tex]x+4\ cm[/tex]

Area of the rectangle is the product of length and width

[tex]\therefore 3990=(x+4)x\\\Rightarrow 3990=x^2+4x\\\Rightarrow x^2+4x-3990=0\\\Rightarrow x=60.198\ or\ -65.198\ cm\\\text{Neglecting negative term}\\\Rightarrow x=60.198\approx 60.2\ cm[/tex]

Width of the rectangle is [tex]60.2\ cm[/tex]

Length of the rectangle is [tex]60.2+4=64.2\ cm[/tex]

ILL GIVE POINTS!!

Suppose a triangle has two sides of length 3 and 4 and that the angle
between these two sides is pi/3 What is the length of the third side of the
triangle?
A. sqrt13
B. 4sqrt3
C. sqrt3
D. 3

Answers

Answer:

no A

Step-by-step explanation:

sqrt13 is the ans

hope it helps

Does the verbal description c minus 12

Answers

Answer:

Yes.

Step-by-step explanation:

Minus and difference mean the same thing. To find the difference, you subtract or minus, so they are the same thing.

On a piece of paper, graph y= see pic

Answers

Answer:

a

Step-by-step explanation:

assuming theyre asking you to graph y = (x-2)(x+3)  -cant see the signs in your photo

the x-intercepts would be 2 and -3 , so option a!

Find in slope intercept form the equation of the line parallel to y + 5x = 2 and passing through the point (-1, 4)

Answers

Step-by-step explanation:

The slope of the line is - 5, the equation will be y=-5x-1.

y+5x=-1

The area of a segment of a circle is the area of the corresponding sector of the circle _____ the area of the corresponding triangle.

Answers

Answer:

The area of a segment of a circle is the area of the corresponding sector of the circle  minus the area of the corresponding triangle.

Step-by-step explanation:

We know area of segment of a circle is the area of the corresponding sector of the circle minus the area of the corresponding triangle.

you hold a sale for $5 sandwiches at your restaurant.you end up selling 359 sandwiches to 245 customers

A. how much money do you have in sandwich sales?

B. how many sandwiches per customer did you sell ?

Answers

Answer:

A. $1795

B. 7

Step-by-step explanation:

Given the following data;

Cost price, Cp = $5

Number of sandwiches sold, Ns = 359 sandwiches.

Number of customers, Nc = 245 customers.

a. To find how much money you have in sandwich sales;

Total amount of money = Cp * Ns

Total amount of money = 5 * 359

Total amount of money, T = $1795

B. To find how many sandwiches per customer did you sell;

Sandwiches per customer = T/Nc

Sandwiches per customer = (1795/245

= 7.33 ≈ 7

solve for x the triangles are the same

Answers

Answer: x=8

Step-by-step explanation:

So to begin with we need to find the connection being that they are the same triangle but with a dilation. We need to find the dilation by matching the new angles with each other H=E F=C and D=G. We need to find the relation ship between CD and FG. 65 divided by 24= 2.6 take ED and multiply 2.6 to find HG. HG= 91. Now we need to find x. 8 times x+ 3=91. Find the closest eight multiple to 91 which is 8 times 8= 88 and add 3 to see it makes 91.

8 is your answer.

Choose the algebraic description that maps the image ΔABC onto ΔA′B′C′.

Question 2 options:

(x,y) → (x – 4,y)


(x,y) → (x,y + 4)


(x,y) → (x,y – 4)


(x,y) → (x + 4,y)

Answers

Answer:

(x,y+4)

Step-by-step explanation:

This shows a translation of 4 units up, so the y coordinate increases by 4. Please mark brainliest as I need 1 more to move up. It would be much appreciated.

Answer:B

Step-by-step explanation:

PLEASE FAST lenear equations

Answers

Answer:

y = 43

Step-by-step explanation:

(y-4)/3 = (y+9)/4

4(y-4) = 3(y+9)

4y-16 = 3y+27

4y-3y = 27+16

y = 43

Find x.

A. 4
B. 4√2
C. 2√2
D. 8

Answers

Answer: D. 8

Explanation:

As shown, x is the hypotenuse and we have an angle 30 whose adjacent side is 4sqrt3. When given an angle and its adjacent side and are required to find the hypotenuse, we may use the cosine of the given angle. Since cosine is adjacent/hypotenuse, we may apply this.

1) cos30 = 4sqrt3/x
2) sqrt3/2 = 4sqrt3/x
3) x/2 = 4sqrt3/sqrt3
4) x/2 = 4
5) x = 8

Hope this helps, brainliest would be appreciated :)

The function fx) = 5 reflected over the y-axis. Which equations represent the reflected function? Select two

Answers

Answer:

y=5

Step-by-step explanation:

f(x) =5 is a line with the equation y=5

when reflected over the y-axis is still y= 5, because we reflected on to itself.

please help me with this trigonometric ratio/terminal arm question, giving brainliest!

Answers

Here is the first half

What is the difference quotient for the function f(x) = 8/ 4x + 1

Answers

Answer:

Last option (counting from the top)

Step-by-step explanation:

For a given function f(x), the difference quotient is:

[tex]\frac{f(x + h) - f(x)}{h} = \frac{1}{h}*(f(x + h) - f(x))[/tex]

In this case, we have:

[tex]f(x) = \frac{8}{4x + 1}[/tex]

Then the difference quotient will be:

[tex]\frac{1}{h}*( \frac{8}{4*(x + h) + 1} - \frac{8}{4x + 1})[/tex]

Now we should get a common denominator.

We can do that by multiplying and dividing each fraction by the denominator of the other fraction, so we will get:

[tex]\frac{1}{h}*( \frac{8}{4*(x + h) + 1} - \frac{8}{4x + 1}) = \frac{1}{h}*(\frac{8*(4x + 1)}{(4(x + h) +1 )*(4x + 1)} - \frac{8*(4(x + h) + 1)}{(4(x + h) +1 )*(4x + 1)})[/tex]

Now we can simplify that to get:

[tex]\frac{1}{h}*\frac{8*(4x + 1) - 8*(4(x + h) + 1)}{(4(x + h) +1 )*(4x + 1)}} = \frac{1}{h}*\frac{-32h}{(4(x + h) +1 )*(4x + 1)}} = \frac{-32}{(4(x + h) +1 )*(4x + 1)}}[/tex]

Then the correct option is the last one (counting from the top)

Find the measure of each angle indicated.
A) 87°
C) 130°
B) 25°
D) 105°

Answers

The answer would be D

mr.brown can type 80 words in two minutes. how many words can he type in 40 minutes?

Answers

Answer:

Step-by-step explanation:

Other Questions
which fraction has a greater value than 0.4 What is one important way that stelae were used?A) for trade with other groups of peopleB) as weapons in warsC) to record information about the growing seasonsD) all of the above On a cold spring afternoon, while walking home from school, I detoured through the playground at the end of our alley. I saw agroup of old men, two seated across a folding table playing a game of chess, others smoking pipes, eating peanuts, andwatching. I ran home and grabbed Vincent's chess set, which was bound in a cardboard box with rubber bands. I also carefullyselected two prized rolls of Life Savers. I came back to the park and approached a man who was observing the game."Want to play?" I asked him. His face widened with surprise and he grinned as he looked at the box under my arm."Little sister, been a long time since I play with dolls," he said, smiling benevolently. I quickly put the box down next to him onthe bench and displayed my retort.What motivates the narrator to "display [her] retort" rather than to respond verbally to the man?the goal not to speak a single negative word in thirty daysthe fear of what the narrator's mother will dothe knowledge that it is dangerous to speak to strangersthe desire to master the art of "invisible strength" What is the approximate length of the line segment?(1, -1)(6,-8) What is the value of x?2367 x= 3/4 , y= - 2/5 then x+ y = NEED THIS QUICK PLSWILL GIVE BRAINLIEST!JournalismPls write in complete sentences and paragraphs! Even though there is freedom of the press, government agencies can decide that information is classified. What does this mean and under what circumstances can the government use this to deny the press access to information? The diagonals of a rhombus are perpendicular find the missing length indicated A sample of 375 college students were asked whether they prefer chocolate or vanilla ice cream. 210 of those surveyed said that they prefer vanilla ice cream. Calculate the sample proportion of students who prefer vanilla ice cream. Find "n" if the Standard Error of Mis 4 and the population standard deviation is 16. A company has two segments with total sales of $500,000 and total variable costs of $343,750. Traceable fixed expenses are $50,000 and common fixed expenses are $80,000. The break even in dollars for the company as a whole equals $ _______. (Enter your answer as a whole number.) if you had to pick between 6 or 9, like the numbers in general which would it be?? just curious Instructions: Find the missing length Which follow-up question best demonstrates attention to the topic and point of view of the speaker? How have you been able to gain so much important knowledge about gardening? What kinds of things do garden members find are beneficial to compost? What differences have you noticed about your garden since switching to compost? Why would you use compost in a garden when fertilizer is inexpensive and easy to use? It takes 25 minutes to fry a burger at Jill street, how long will it take to fry 13 burgers 8 I hate shopping _____ clothes. A to B by C for 9 My brother borrowed $10 _____ me last month. A from B by C to 10 It isn't a good idea to get _____ debt. A for B into C on 11 He paid for dinner _____ cash. A in B for C by 12 The hotel charged me $25 _____ a two-minute phone call! A for B of C from 13 Tina still hasn't paid me _____ the money I lent her! A with B back C up Brown Co. issued $100 million of its 10% bonds on April 1, 2016, at 99 plus accrued interest. The bonds are dated January 1, 2016, and mature on December 31, 2035. Interest is payable semiannually on June 30 and December 31. What amount did Brown receive from the bond issuance? a) $87.8 million b) $99.0 million c) $100.0 million d) $101.5 million Please help!! :)For this circuit, what will be the voltage drop across R1? A. 21.3 VB. 14.2 VC. 45.0 VD. 9.47 V Lucy's dog sleeps 14 hours a day. What percent of the day does her dog spend sleeping?