Friday

November 21, 2014

November 21, 2014

Total # Posts: 278

**Geometry**

Conic sections: Ellipse Show that the distance between the directrix and center is D1C = a/e. F1V1 + F1V2 = eD1V1 + eD1V2 2a = e(D1V1 + D1V2) = e(D1V1 + [D1V1 + V1V2]) = e(D1V1 + V1V2 + V2D2) = e(D1V1 + V1C + + CV2 + V2D2) = e([D1V1 + V1C] + [CV2 + V2D2]) = e([D1C] + [CD2]) 2a...
*November 9, 2014*

**Algebra**

Belle is swimming in the lake and is 230 feet from shore. She starts to head back to shore at arate of 2ft/s. Ten seconds later, Max hops in a row boat and rows towards Belle at a rate of 5 ft/s. How many seconds will Bell have been swimming when Max reaches her?
*October 16, 2014*

**Algebra**

Please help I am lost on this one and another one i posted
*October 16, 2014*

**Algebra**

A car leaves Denver at 30 km/h traveling south. Two hours later, another car leaves Denver traveling south at 40 km/ h. How many hours had the first car been traveling when the second car catches up?
*October 16, 2014*

**Algebra**

The length of a rectangle is 3 times the width. If the length is increased by 4 cm and the width is decreased by 1cm the parimeter will be 102 cm. find the dimensions of the original rectangle. I don't know the equation, please show the work. Not just the answer. So I can ...
*October 16, 2014*

**math**

Four ways to determine a plane: 1) two parallel lines 2) two intersecting lines 3) three noncollinear points 4) a line and a point not on the line
*October 9, 2014*

**math factoring**

factor 2x^4+12x^3-18x^2-108x
*October 5, 2014*

**chemistry**

If He(g) has an average kinetic energy of 7590 J/mol under certain conditions, what is the root mean square speed of F2(g) molecules under the same conditions?
*September 28, 2014*

**MATH**

How do i find the center of a circle using 3 points. Also need to find the radius and the equation of the circle.... My 3 points are (2,8) (-4,6) (1,-1) I found the Equation of the perpendicular bisector of the line between the first and second point which was y=(3/2)x + 5 And...
*September 25, 2014*

**Please Help! Math**

How to find the center and radius of a circle using 3 points... My 3 points are (2,8) (-4,6) (1,-1) I found the Equation of the perpendicular bisector of the line between the first and second point which was y=(3/2)x + 5 And the Equation of the perpendicular bisector of the ...
*September 25, 2014*

**business**

. You've written a check to Goodwill Supply, and the check has been lost. What should you do? A. Stop payment on the first check; then write a second one. B. Send a counter check to Goodwill. C. Write another check immediately. D. Call Goodwill and tell them you'll ...
*September 22, 2014*

**office**

Which of the following organizations would most likely use an unabridged dictionary? A. The English department at a large university B. An automotive dealership C. A large retail department store D. A pediatrics hospita
*September 19, 2014*

**Algebra help**

I know how to get the slope. In my answer key it has the solution of -1\3x +10/3 What i don't get is how they got the +10/3 part
*September 17, 2014*

**Algebra help**

Find an equation of the line L, where L is perpendicular to y=3x and passes through the point (1,3) Please help I'm not sure what formula to use or how to work out this problem
*September 17, 2014*

**Algebra**

Use a graphing utility to approximate the real solutions if any, of the given equation rounded to two decimal places. x^3-9x+1=0
*September 17, 2014*

**math**

Are the two solutions to x (2x+1) = 1 found by setting x = 1 and 2x + 1 = 1? Explain your reasoning. What are the solutions to this equation? Show how you arrived at your answer. Create an equation for your classmates to solve that requires factoring.
*July 3, 2014*

**aLGEBRA**

5/4X+7/12=1/3X-1/6
*May 14, 2014*

**math **

ABCD is a rectangle. If AC = 2(5a + 1) and BD = 2(a + 1), find the length of each diagonal.
*May 9, 2014*

**Chem.**

At equilibrium, the concentrations in this system were found to be [N2]=[O2]=0.200 M and [NO]=0.500 M. N2 + O2= 2NO If more NO is added, bringing its concentration to 0.800 M, what will the final concentration of NO be after equilibrium is re-established?
*April 1, 2014*

**microeconomics**

a
*March 30, 2014*

**English IV**

Help Please! Choose the function of the italicized infinitive phrase shown below. (stars indicate italicized infinitive phrase) Meridith is *to be restored as captain.* Answer Options: Function of infinitive: Adjective, Adverb, or Noun. (I chose adverb & got it wrong)
*February 20, 2014*

**Chemistry:Important!!!!!!!**

Thank you! I was just missing the step of multiplying by atomic mass! :)
*February 10, 2014*

**Chemistry:Important!!!!!!!**

A student begins with 9.7 mL of a 0.26 M Cu(NO3)2 solution and performs copper cycle lab. She recovers 0.075 grams of copper metal. A) What is the Theoretical Yield B) What is the Actual Yield C) What is the Percent Yield
*February 10, 2014*

**office finances**

the answer is B. stub
*December 28, 2013*

**Social Studies**

idk pls help
*December 23, 2013*

**engineering**

No idea. But i want to know. Does anyone have an idea??
*December 19, 2013*

**Finance**

The spot exchange rate for the Canadian dollar is Can $1.14 and the six-month forward rate is Can $1.17. Calculate whether a U.S. dollar or a Canadian dollar is worth more.
*December 17, 2013*

**chemistry **

Q2: A sample of carbon dioxide(CO2) has a mass of 55g and occupies 3.3L at 100C. What pressure does the gas exert (in kPa)?
*December 8, 2013*

**chemistry **

Q3: In the combustion reaction of 149g of propane(C3H8) with excess oxygen, what volume of carbon dioxide(CO2) is produced at STP? (note: balance the reaction first) C3H8 + O2 3CO2 + H2O
*December 8, 2013*

**chemistry **

Aluminum granules are a component of some drain cleaners because they react with sodium hydroxide to release both energy and gas bubbles to help clear the drain clog. The reaction is: 2NaOH + Al + 6H2O 2NaAl(OH)4 + 3H2 (note: balance the reaction first) What mass of ...
*December 8, 2013*

**algebra 2**

3x+3y
*December 1, 2013*

**mahs**

(2a+8b)
*December 1, 2013*

**chemistry**

What volume of carbon monoxide gas (at STP) is needed when 1.31 moles of oxygen gas react completely in the following equation? 2 CO + O2 --> 2 CO2
*November 10, 2013*

**chemistry**

What mass of ammonia is produced when 1.48 L of nitrogen (at STP) react completely in the following equation? N2 + 3H2 --> 2NH3
*November 10, 2013*

**BioChem**

In yeast, ethanol is produced from glucose under anaerobic conditions. What is the maximum amount of ethanol (in millimoles) that could theoretically be produced under the following conditions? A cell-free yeast extract is placed in a solution that contains 2.50 × 102 ...
*October 30, 2013*

**Biochem**

In yeast, ethanol is produced from glucose under anaerobic conditions. What is the maximum amount of ethanol (in millimoles) that could theoretically be produced under the following conditions? A cell-free yeast extract is placed in a solution that contains 2.50 × 102 ...
*October 30, 2013*

**General chemistry**

123
*October 16, 2013*

**Stats**

The time that it takes a randomly selected job applicant to perform a certain task has a distribution that can be approximated by a normal distribution with a mean value of 150 sec and a standard deviation of 20 sec. The fastest 10% are to be given advanced training. What task...
*October 2, 2013*

**fractions**

a recipe calls for 1/4 teaspoon of salt. to make three times the amount how much salt is needed?
*September 24, 2013*

**chemistry**

density = mass/volume mass = 6.4 grams volume = 28.61 mL - 27.80 mL = 0.81 mL density = 6.4 grams/0.81 mL density of Fe = 7.9 g/mL
*August 29, 2013*

**Precalculus**

Thank you!! I combined the terms when I isolated the LCD and received the following: a^2 +5a - 2a - 10 = 3a^2 + 15a etc..until I received: 2a^2 + 12a + 10 = 0 I wasn't sure what step to complete in order to obtain -5/2 as my final answer.
*August 29, 2013*

**Precalculus**

Is a+5 the proper LCD to isolate from the equation in order to obtain -5/2?
*August 29, 2013*

**Precalculus**

Solve for a. a/a+5 - 2 = 3a/a+5
*August 29, 2013*

**Pre-Calculus**

How to write this conic section in standard form? 3y^2 = 108 - 12x^2
*June 5, 2013*

**Pre-Calculus**

How to write this conic section in standard form? 3y^2 = 108 - 12x^2
*June 5, 2013*

**Physics**

its a mystery
*May 24, 2013*

**chem**

a grocery store sells vinegar in 1Lbottles. based on your results, how many grams of acetic acid are in a bottle?
*May 13, 2013*

**math**

use r=3/2, nowhere does it say r is an integer. 64,96,144,216,324,486
*May 12, 2013*

**physics**

23.4444444444444444
*May 11, 2013*

**math**

The buying and selling commission schedule shown below is from a well-known online discount brokerage firm.? Taking into consideration the buying and selling commissions in the schedule find annual rate of interest earned by each investment? Transaction Size Commission Rate $0...
*May 2, 2013*

**Physics**

Tut tut, your supposed to do your own MIT exam questions, not ask other to do them for you.
*April 27, 2013*

**Chemistry**

Determine how many milliliters of 0.370 M HClO4 will be required to neutralize 58.99 g Ca(OH)2 according to the reaction: 2HC1O4+Ca(OH)2>CaC1O4)2+2H2O How would I set this up?
*April 19, 2013*

**Chemistry**

Determine how many milliliters of 0.370 M HClO4 will be required to neutralize 58.99 g Ca(OH)2 according to the reaction: 2HC1O4+Ca(OH)2>CaC1O4)2+2H2O How would I set this up?
*April 19, 2013*

**Chemistry**

Calculate the [H+] for: black coffee with a pH of 6.9 (Enter your answer as follows: 1.0E-2 for 0.010)
*April 19, 2013*

**social studies**

How can you remember facts about the revolutionary war
*April 16, 2013*

**Chemistry**

How many kilojoules of energy are needed to convert 104 g of ice at -14.6 to water at 25.8°C? (The specific heat of ice at -14.6 is 2.01 J/g°C.)
*April 4, 2013*

**Chem**

(Sp Heat)(Change in Temp)(Mass)=
*April 4, 2013*

**Chemistry**

The specific heat of zinc is 0.096 cal/(g °C). Determine the energy required to raise the temperature of 26.1 g of zinc from room temperature (20.0 °C) to 150 °C.
*April 3, 2013*

**Chemistry**

How many joules of energy are needed to change 275 g of water from 15°C to steam at 100.°C?
*April 3, 2013*

**Legal aspects of health Information management**

Im wondering, too!
*March 22, 2013*

**Chemistry **

What is the hydroxide ion concentration of a 0.370M oxalic acid, H2C2O4, solution? For oxalic acid, Ka1=5.6x10^-2 and Ka2=5.1x10^-5
*March 19, 2013*

**Chemistry **

What is the concentration of CO3^-2 in a 0.028M solution of carbonic acid, H2CO3? For carbonic acid, Ka1=4.2x10^-7 and Ka2=4.8x10^-11
*March 19, 2013*

**PHYSICS**

A bottle containing 4 kgof water at a temperature of 15°Cis placed in a refrigerator where the temperature is kept at 2°C.How much heat is transferred from the water to cool it to 2°C?
*March 18, 2013*

**math**

A box contains four red, three blue, and six green lenses. Two lenses are randomly selected from the box. Find the probability of getting two red lenses when two are selected if the first selection is NOT replaced before the second selection is made.
*March 3, 2013*

**Cosmology**

The abundance of irregular galaxies across clusters
*March 1, 2013*

**bioelectricity**

Let Pk, Pna and Pcl be permeabilities of squid axon membrane for potassium, sodium and chloride, respectively. During the rest, the ratios of permeabilities are given by Pk:Pna:Pcl = 1.0 : 0.043 : 0.44 During the peak of an action potential these ratios become Pk:Pna:Pcl = 1.0...
*February 19, 2013*

**bioelectricity**

Cl equil-v: Only chloride may cross a membrane separating two compartments. At a temperature of 26∘C, the concentrations of chloride ions are: intracellular: 70 extracellular: 485 What is the equilibrium potential? Give a numeric answer within 1%, in mV.
*February 19, 2013*

**Bioelectricity**

K equil-v: Only potassium may cross a membrane separating two compartments. At a temperature of 30∘C, the concentrations of potassium ions are: intracellular: 280 extracellular: 110 What is the equilibrium potential? Give a numeric answer within 1%, in mV.
*February 19, 2013*

**Bioelectricity**

Na equil-v: Only sodium may cross a membrane separating two compartments. At a temperature of 28∘C, the concentrations of sodium ions are: intracellular: 100 extracellular: 485 What is the equilibrium potential? Give a numeric answer within 1%, in mV.
*February 19, 2013*

**bioelectricity**

At a temperature of 10∘C, the concentrations of ions are: IonIntracellularExtracellular Na61485 K28010 Cl51485 The transmembrane potential is -30 mV. How many ion species (Na, K, or Cl) are NOT in equilibrium?
*February 19, 2013*

**bioelectricity**

Assume that frog muscle cell membrane is permeable to Na and K only. The membrane permeabilities for Na and K are Pna and Pk respectively. At 16∘C, the resting membrane is -91 mV. What is the ratio of permeabilities Pna/Pk? For frog muscle, intracellular and ...
*February 19, 2013*

**math**

Ryan estimates that he uses 2/3 cup of syrup each time he eats pancakes. How many times will he be able to eat pancakes without running out of syrup if he has a giant bottle of syrup that contains 48 cups. Do you multiply 48x2/3 and get that he will be able to eat 32 pancakes?
*February 13, 2013*

**Physics**

A mountain-climbing expedition establishes two intermediate camps, labeled A and B in the drawing, above the base camp. What is the magnitude Δr of the displacement between camp A and camp B?
*January 31, 2013*

**Chem**

how to prepare a 250 mL solution of .15 M K2SO4 with a volumetric flask
*January 15, 2013*

**Grammar**

Need thesis stAtement for persuasive research paper on cs lewis
*January 10, 2013*

**Physics**

Car A is traveling at 18 m/s and car B at 25 m/s. Car A is 300m behind car B when the driver of Car A accelerates his car with an acceleration of 1.80m/s^2. How long does it take car A to overtake car B?
*January 8, 2013*

**math**

List order of numbers from least to greatest is the following correct? 1 3/7 1 2/4 1 8/14 1 3/4
*January 8, 2013*

**physics**

If the hockey puck lies on the ice and is struck by a hockey stick with a force of 2.60e+03 N, what is the acceleration of the hockey puck
*January 1, 2013*

**HISTORY HELP ME**

oh thats cool way to show feelings
*December 19, 2012*

**HISTORY HELP ME**

i think it d
*December 19, 2012*

**HISTORY HELP ME**

28. Which answer best describes how some enslaved African Americans expressed their emotions? (4 points) They didn’t believe in public emotional displays, so they would often express themselves only to the tribal chief. They participated in sports like archery and ...
*December 19, 2012*

**math**

Estimate each quotient 535.6/35?
*November 27, 2012*

**Physics**

A monatomic ideal gas expands from 1.00m^3 to 2.50m^3 st a constant pressure of 2.00x10^5 Pa. Find the change in the internal energy of the gas.
*November 24, 2012*

**Physics**

An engine does 15kJ of work while rejecting 37 kJ to the cold reservoir. What is the efficiency of the engine?
*November 23, 2012*

**Chemistry**

(a)What is the bond order of the diatomic molecule BN? (b) Is BN paramagnetic? (c) Rank the following compounds in order of increasing bond energy: B2, N2, BN. (d) Rank the following compounds in order of increasing bond length: B2, N2, BN.
*November 18, 2012*

**Science**

Jiskha is not part of the MITx platform!!! How the honor code of MITx could be applied to an user of other system?
*November 18, 2012*

**Chemistry**

Rb<Se<Cl
*November 18, 2012*

**Chemistry**

right!!!
*November 18, 2012*

**Chemistry**

right!!!
*November 18, 2012*

**Chemistry :'(**

right!!!
*November 18, 2012*

**Chemistry :(**

(Kg og Na)/ 23*4 =X X * 47.88 = in g convert to Kg
*November 18, 2012*

**Chemistry**

-430.5
*November 17, 2012*

**chemistry**

equation?
*November 17, 2012*

**chemistry**

-430.5
*November 17, 2012*

**chemistry**

equation please
*November 17, 2012*

**math**

what is 14.76 rounded to the nearest hundredth?
*November 16, 2012*

**science**

-430.5
*November 16, 2012*

**physics**

blocks 1 and 2 of masses 2 kg and 4kg, respectively, are connected by a light string, as shown above. These blocks are further connected to a block of mass 3kg by another light string that passes overr a pully of negligible mass and friction. Blocks 1 and 2 move with a ...
*November 13, 2012*