# Posts by David

Total # Posts: 2,324

math
The parabola whose equation is 4y^2+3x=2+8y, determine the co-ordinates of the focus, equation of the directrix and the length of the latus rectum?

Algebra
Country A has a growth rate of 4.7% per year. The population is currently 5,646​,000 and the land area of Country A is 13​,000,000,000 square yards. Assuming this growth rate continues and is​ exponential, after how long will there be one person for every ...

Math
A rectangle, a circle and a triangle are drawn in a plane. What is the maximum number possible points of intersection. The sides of the triangle are not collinear with any of the sides of the rectangle.

Algebra
Country A has a growth rate of 2.6% per year. The population is currently 4,069​,000 and the land area of Country A is 33​,000,000,000 square yards. Assuming this growth rate continues and is​ exponential, after how long will there be one person for every ...

Math
Find two algebraic expressions for the area of each figure. First, regard the figure as one large rectangle, and then regard the figure the figure as a sum of four smaller rectangles t,5,t,3

History
Thank you so much! I'm behind a lot in World History.

Math
What is the equivalent ratio in simplest form of 45 books in 90 minutes if she organized 120 books.

Science, NATS
Consider the following chemical reaction. Molecular hydrogen and carbon dioxide react to form water and methane. H2+CO2-->H2O+CH4 A)Explain why this equation is not balanced and what law of nature does it break in its current form? B) Astronauts from the Earth carry large ...

math
4 t shirts. 2 sandals

math
After 5 seconds

Math
13.64 minutes

Math
1.25L of water

math
mamta read 2/5 of a book on monday and 3/8 of the remaining book on tuesday.find the part of the book left unread after tuesday find the total no of pages in the book if 48 pages are left unread.

Social studies
Life expectancy What two countries are not part of Africa?

maths
How many even numbers can be formed from the digits 1,2,4,4,7,8,9 Is it 2160 ( 6! * 3)

Math
75 red ballons

history,college
If you are not that sure to rewrite it or not, you may actually check it at the professional service I use all the time. I recommend Marvelous essay service where you can get the help on time.

Maths ( permutation and combination)
a town council plans to plant 12 trees along the centre of a main road.It has 4 hibiscus trees, 6 Jacaranda trees, 2 oleander trees. How many different arrangements of these 12 trees can be made if no hibiscus tree is next to another

Psychology
I do not really understand the topic of your research and I think that the answers will be good only if the question is stated in the proper way too. Please, check what can be done at the professional service I use all the time. Go to Marvelous essay service

Physics
100m

maths
If it takes 10 men to build a house in 6 months how many men would be needed to build it in 4 months

maths need help
x^(e^3x)^x Find the derivative of that please show working thanks

integrated science
A planet is 2.45 x 10^9 km away. How long would it take in hours to travel to the planet at the speed of light? (speed of light is 2.998 x 10^8 m/s)

math
100 student appeared in class test for a combined english and hindi examination. 70 students passed in both,8 failed in english and hindi and 5 failed in hindi only find how manystudents failed in english and how many students passed in hindi also find how many students passed...

Math
Eduardo has a red 6-sided number cube and a blue 6-sided number cube. The faces of the cubes are numbered 1 through 6. Eduardo rolls both cubes at the same time. The random variable X is the number on the red cube minus the number on the blue cube. What is P(−2≤X...

Chemistry
Calculate how many grams of the substance and how many grams of water is in a solution of 400g with a concentration of a 30%

Chemistry
Calculate the mass of the precipitate formed when 2.27 L of 0.0820 M Ba(OH)2 are mixed with 3.06 L of 0.0664 M Na2SO4.

Chemistry
How many mL of 0.1 N NaOH are required to react with 100 mEq of H2SO4?

Chem
Write a chemical formula. . . Ca2+ and S2-

Chem
Consider the following equation in chemical equilibrium C2H4(g) <--> C2H6(g) + 137 kJ What happens to the ethane (C2H6) when the temperature of the system is increased

maths
The function f is such that f(x)= (2 - x)^2, x belongs to real number. Find g and h as functions of x such that gh(x)=f(x)

computer ( theory )
A designer wishes to include some multimedia components on a web page. a) If the designer has some images stored in files, there are two possible formats for the files.. i) Describe the approach used if a graphic is stored in a vector graphic file ii) Describe the approach ...

CHEMISTRY
I didn't understand the mass M2CO3 titrated = 7.46 x (25/1000) step. please, could you explain

CHEMISTRY
A solution of a metal carbonate M2CO3, was prepared by dissolving 7.46 g of the anhydrous solid in water to give 1000cm^3 of solution. 25.0cm^3 of this solution reacted with 27.0cm^3 of 0.100 mol/dm^3 hydrochloric acid. Calculate the relative formula mass of M2CO3 and hence ...

Organic Chemistry
Suppose 5.00 gram of a mixture of aspirin, caffeine, and acetanilide was dissolved in enough solvent (methylene chloride) to make a total of 100.00 mL volume. You took 10.00 mL from it and isolated its components using the same protocol you did in the lab. You obtained: ...

Geometry
If the width and height of a rectangular prism are each shrunk to one seventh of the original size but the length remains the same, what is the formula to find the modified surface area?

math
Find the smallest positive integer not relatively prime to 2015 that has the same number of positive divisors as 2015.

math
If I am traveling at 60mph and you are traveling at 30mph how many minutes until we meet?

math
Marta’s math textbook weighs mc017-1.jpg of a pound less than 4 times the weight of the book she is reading for her language arts class. If the weight of the math textbook is mc017-2.jpg pounds, which shows the correct equation and value of x, the weight of Marta’s ...

Parametric Equations
For the set of parametric equations x = 2t+1 and y = t^2-5, name the initial point on the graph on the interval -5<t<5. a. (-9, -30) b. ( -5, 5) c. (11, 20) d. (-9, 20) (I chose this one)

Math
What must be true about the solution to this system of equations? x+4y+9z = -96 -2y+9z = -47 z = -7 a) The solution will describe the intersection point(s) of the 3 graphs. b) The value of z must be -7. c) The solutions will have values for x, y, and z. d) All of the above ...

math
A rectangle has a width of 15 inches and a diagonal of 17 inches. Find the length of the rectangle in inches. 15^2 + b^2 = 17^2 225 = b^2 = 289 0 + b^2 = 289 – 225 B^2 = 64 B = SQRT of 64 = 8 The length of the rectangle in inches equals 8 inches.

math
A suitcase measures 22 inches long and 16 inches high. What is the diagonal length of the suitcase to the nearest foot. 16^2 + 22^2 = C^2 256 + 484 = C^2 740 = C^2 SQRT of 740 = 27.20 in. The diagonal length to the nearest foot equals 2.26ft.

math
A suitcase measures 22 inches long and 16 inches high. What is the diagonal length of the suitcase to the nearest foot. 16^2 + 22^2 = C^2 256 + 484 = C^2 740 = C^2 SQRT of 740 = 27.20 in. The diagonal length to the nearest foot equals 2.26ft.

Math
A hat contains 3 ​marbles; one green​, one blue​, and one orange. Two marbles are selected at random without replacement from the hat. ​a) Determine the number of points in the sample space. ​b) Determine the probability of selecting exactly 1 ...

At a​ homeowners' association​ meeting, a board member can vote yes or on a motion. There are three motions on which each board member must vote. Complete parts ​(​a) through ​(c) below. ​(a) Determine the number of points in the sample ...

Math
Find the indicated probability. If​ P(A or ​B)equals=0.7 ​P(A)equals=0.3 and​ P(A and ​B)equals=0.15 find​ P(B). ​P(B)equals=

Science
Why are boats more efficient than airplanes? They use less fossil fuels to move

Math
One thousand raffle tickets are sold for 1 dollar each, one prize of 800.00 dollars is to be awarded. Rene Condos purchases one ticket a) Determine her expected value? b) Determine the fair price of a ticket?

Prosbility
One thousand raffle tickets are sold for 1 dollar each. One price of 800.is to be awarded. Rena Condos purchases one ticket? Determine her expected value Determine the fair price of the ticket 1/800 1 dollar

Physics
8kg mass moving with a speed of 30 of 30ms-1 is brought to rest in 2.5sec, calculate the magnitude of the constant retarding force

algebra 1
NEED HELP!!Hi, I have been trying to figure this one math problem for awhile and I am stuck. I believe the answer is between A or B. Skip is practicing tennis serves against a wall. The distance between Skip and the tennis ball, in feet, at any time T, measured in seconds, is ...

Algebra
The Connecticut River flows at a rate of 3 km / hour for the length of a popular scenic route. If a cruiser to travels 3 hours with the current to reach a drop-off point, but the return trip against the same current took 7 hours. Find the speed of the boat without a current?

math
-5 + (x/-3) = 28

Math
Find the limit if it exists. lim 1/(x-2) = infinity x→2+ lim 1/(x-2) = negative infinity x→2- lim 1/(x-2) = Does not exist x→2 lim (3x+2) = infinity x→∞ lim 999/(x^3) = 0 x→-∞ Can someone check to make sure that I am correct?

Math
Find the limit if it exists. lim 1/(x-2) x→2+ lim 1/(x-2) x→2- lim 1/(x-2) x→2 lim (3x+2) x→∞ lim 999/(x^3) x→-∞

Math
Find the limit if it exists. lim 1/(x-2) x→2+ lim 1/(x-2) x→2- lim 1/(x-2) x→2 lim (3x+2) x→∞ lim 999/(x^3) x→-∞

Math
Ellie has 200 dollars in her wallet at 10:00 AM when she goes to the mall. Afterwards, at 4 PM she has only 5 dollars left. Is it possible that Ellie had exactly 100 dollars at one point? Explain. My guess to this question would be yes and I would use the Intermediate Value ...

Math
f(x) = 2x^2 x<2 4x x≥2 1. Find the slope of the tangent curve of 2x^2 at x=2. a. -1/2 b. 1/2 c. 4 d. 8 e. Does not exist 2. Find the slope of the tangent curve of 4x at x=2. a. -1/2 b. 1/2 c. 4 d. 8 e. Does not exist 3. Find the slope of the tangent curve of f(x) at x...

Math
5x - 3 = 7x + 11 x=-4 3w -4 = w+8 w =6 Please check. Thanks

philosophy
Why are philosophical questions not answered with facts?

math
#1 is not correct reiny lmao

math
#1 is not correct lmao

english
a letter to your uncle in american asking him to help you pay your school fees for this term.

Chemistry
The reaction of methyl-benzene with HNO3 in the presence of catalyst will provide what main compound?

math
The radius of a circle in increasing at the rate of 0.5cm/s. Find the rate at which the circumference increases if the radius in 5cm.

Calculus
A bucket begins weighing 30 pounds, including the sand it holds. The bucket is to be lifted to the top of a 25 foot tall building by a rope of negligible weight. However, the bucket has a hole in it, and leaks 0.1 pounds of sand each foot it is lifted. Find the work done ...

chemistry
1 mole ----> 24 g ? mole -----> 0.12 moles ( Mg ) = 0.12 / 24 = 0.005 moles of Mg

Chemistry
DrBobb22 Calcule the concentrations of Cd^+2 , [Cd(CN)4^-2] and CN^- at equilibrium, when 0.42 moles of Cd(NO3)2 dissolves in 1 L of 2.50 M NaCN Kf for Cd(CN)4^-2 is 7.1x10^16

Chemistry
I will post again ok?

Chemistry
Kf is 7.1 x 10^16

Chemistry
DrBobb22 Calcule the concentrations of Cd^+2 , [Cd(CN)4^-2] and CN^- at equilibrium, when 0.42 moles of Cd(NO3)2 dissolves in 1 L of 2.50 M NaCN Kf for Cd(CN)4^-2 Help!

Chemistry
Calculate the concentrations of Cd+2 , Cd(CN)4^-2 and CN at equilibrium when dissolvs 0.42 moles of Cd(NO3)2 (2.50 mol/L) Kf for Cd(NO3)2 = 7,1x10^16.

Chemistry
What volume in ml of 0.500 M silver nitrate is required to completely react with 25.0 ml of 1.5 M calcium chloride?

Math
f(x) = cos (1/x) Find the limit as x approaches infinity and find the limit as x approaches negative infinity. Identify all horizontal asymptotes.

Math
f(x) = cos (1/x) Find the limit as x approaches infinity and find the limit as x approaches negative infinity. Identify all horizontal asymptotes.

mathematics for accounting
the question is the formula use in calculating depreciation that is reducing balance method which is (1-n√s/c)×100/1 now we were asked to now make each of n,s,and c in the formula the subject of the formula

math
make each of the following the subject of the formula n,s,c in (1-n√s/c)*100/1

Math
f(x) = tan x / sin x Find the vertical asymptote. Describe its behavior to the left and right of the vertical asymptote.

Chemistry
This is the correct one because you simply just have to do a double replacement reaction. H3PO4 + 3KOH -> K3PO4 + 3 H2O

Chemistry
This is the correct one because you simply just have to do a double replacement reaction. H3PO4 + 3KOH -> K3PO4 + 3 H2O

Quantitative Chemistry
(H: +1, Cl: -1) (Mn: +4, O: -2) --> (Mn: +2, Cl: -1) (H: +1, O: -2) (Cl: 0) So, as you can see the Manganese atoms are clearly being reduced which means that it is gaining electrons, so the charge goes down. You can now eliminate choice A. Next, we can see that the charge ...

Geometry
Find the volume of the large solid without the smaller solid. The solid is a right solid and is not drawn to scale. Round answers to the tenths place.

Math
Thanks sir

Math
A bucket begins weighing 15 pounds, including the sand it holds. The bucket is to be lifted to the top of a 50 foot tall building by a rope of negligible weight. However, the bucket has a hole in it, and leaks 0.1 pounds of sand each foot it is lifted. Find the work done ...

Math
Thanks Damon!

Math
kinematics look easier i can do both ways but will they have different values

Math
its calculus but will kinetatic equations work as well?

Chemistry
Consider the reaction: K2S(aq)+Co(NO3)2(aq)=2KNO3(aq)+CoS(s) what volume of 0.255 M K2S solution is required to completely react with 160 mL of 0.130 M Co(NO3)2?

Chemistry
Thanks!!!

History
The answer is dessert

Calculus 2
Suppose that a spring has a natural length of 25 ​cm, and that 8 J of work is needed to stretch from a length of 50 cm to 80 cm. How far beyond its natural length will a force of 32 N keep the spring​ stretched? **I've tried calculating the spring constant ...

Government
Why people who represents special interest group received the name lobbyist ?

Programming
I am having a problem with something. i nead to assing values to parameters from input.dat file without using fscanf. i need to use the terminal like a.out<input.dat>output.out i have a file like this GEN 0.0 2.1351 0.00001 500 o PEND 0.12 0.1 0.15 0.5 0 0.16 0.11 0.8 -0...

algebra 2
Write (21 − 4i) − (16 + 7i) + 28i as a complex number in standard form.

Chemistry
[2.0 mol (-285.91 kJ/mol)] + [1.0 mole (0 kJ/mol)] - [1.0 mole (50.61 kJ/mol)] = ??? I came up with the answer of -622.43 but im not sure what the correct amount of significant figures would be and why? would 0 kj/mol be considered significant making the answer -600? what ...

have got a question@sir-damon
so how can i get the total

maths help plz
A certain number of children are arranged in a circular form,if they are evenly spaced,the 7th child is directly opposite to the 8th child.... how many children are their altogether? thanks

History
Why is the Franco-Prussian War considered an important development in the history of Europe? It was at this time that France reclaimed its military dominance in Europe. It was because of this war that Germany began its military dominance in Europe. The war allowed Prussia to ...