Friday
December 19, 2014

Posts by ann


Total # Posts: 1,265

physics
In the construction of bridges and skyscrapers, gaps must be left between adjoining steel beams to allow for the expansion and contraction of the metal due to heating and cooling. The temperature of a sample of iron with a mass of 10.0g changed from 50.4oC to 25.0oC with the ...
November 3, 2013

Science
a wagon that has a mass of 8kg? If the net force on a wagon is 4N, what is the wagon’s acceleration?
November 3, 2013

Pre-Calculus
thanks
November 3, 2013

Pre-Calculus
How is -16/(4x+6)^5 and -1/(2(2x+3)^5) equivalent? I think -1/2(2x+3)^5 is the more simplified version of the two, but I just can't figure out how -16/(4x+6)^5 simplifies to -1/(2(2x+3)^5). please explain
November 3, 2013

angelina's answer
no, it's 1,3,5,7,9,11 and 2,4,6,8,10,12
November 1, 2013

Pre-Calculus
thank you
October 31, 2013

Pre-Calculus
Let f(x) = [(√x)-7]/[(√x)+7]. What is f'(x)? What is the easiest way to find the derivative of this? Should I remove all the radicals and use quotient rule, like f'(x)= ((x^0.5) + 7)(0.5x^-0.5) - ((x^0.5)-7)(0.5x^-0.5) / ((x^0.5) + 7)^2 Is this right? How ...
October 31, 2013

math
find an equation of the line passing through the pair of points. write the equation in Ax+By=C (-9,7), (-10,-4)
October 29, 2013

math
find an equation of the line with the given slope that passes through the given point. write the equation in the form Ax+By=C M=3/2, (7,-3)
October 29, 2013

Ancient History Art
Can the extravagance and costs, both of money and lives, be justified in the opulent architecture commissioned by "divinely empowered" individuals of ancient cultures? Name a comparable example from today's society.
October 27, 2013

math
ok 35020/1.03=34000 ....but where did the 1.03 come from?
October 23, 2013

math
Find last years salary if after a 3% pay raise this years salary is $35,020
October 23, 2013

Pre-Calculus
this is weird...but thanks!
October 19, 2013

Pre-Calculus
Determine the derivative at the point (2,−43) on the curve given by f(x)=7−7x−9x^2. I know that the answer is -43, but I was wondering if it was just a coincidence that the derivative at the point (2,−43) is -43, or is there a reason why -43 is the same...
October 19, 2013

Pre-Calculus
Thank you very much
October 18, 2013

Pre-Calculus
Yeah, that was a stupid mistake... But now I have another question. Isn't the final answer supposed to be in −1/(ah+b) form? Why is my answer 1/(196+14h) still positive? Did I do something else wrong?
October 18, 2013

Pre-Calculus
Let f(x) be the function 1/(x+9). Then the quotient [f(5+h)−f(5)]/h can be simplified to −1/(ah+b). What does a and b equal to? So I understand the overall concept, and did f(5+h) = 1/(14+h) and f(5) = 1/14. Then to subtract the two, you get the common denominator ...
October 18, 2013

Pre-Calculus
The Hotel Ventor has 400 rooms. Currently the hotel is filled. The daily rental is $ 600 per room. For every $6 increase in rent the demand for rooms decreases by 7 rooms. Let x = the number of $ 6 increases that can be made. What should x be so as to maximize the revenue of ...
October 14, 2013

Pre-Calculus
Nevermind, now I see that all the question asks for is the y-intercept. Why didn't I see that before...
October 14, 2013

Pre-Calculus
It has been found that the supply of golf clubs varies linearly with its price. When the price per item was $ 76.00 ,32 items are supplied; When the price was $ 90.25 , 70 items are supplied. What is the lowest price above which golf clubs will be supplied ? So I know the ...
October 14, 2013

geometry
find measurement angle bac db and dc are paralell, da intersects bc, angle a is 65 degrees so i multipied by two and came up with the answer 130 degrees, is this correct? thanks
October 14, 2013

Pre-Calculus
I tried and got 3.371880575, but I think I'm still wrong...
October 9, 2013

Pre-Calculus
You are given a pair of equations, one representing a supply curve and the other representing a demand curve, where p is the unit price for x items. −p+0.0208333333333333x+2=0 and p = √(57-x) What is the market equilibrium for x? I know I'm supposed to set both...
October 9, 2013

Pre-Calculus
Actually I think you used the wrong function. The 1st one is the demand, not the second.
October 8, 2013

Pre-Calculus
You are given a pair of equations, one representing a supply curve and the other representing a demand curve, where p is the unit price for x items. 466p+90x−2390=0 and 484p−22x−978=0 Determine the revenue function. Revenue function R(x)=? I got (-90x/466...
October 8, 2013

Pre-Calculus
For the function f(x)=3x^3−42x Compute the difference quotient [f(x+h)−f(x)]/h,h≠0 I checked my work like 3 times and still got [(-2x^3)+(3hx^2)+(3xh^2)+(h^3)-(42h)]/h Is it wrong?
October 7, 2013

Pre-Calculus
Oh yeah I forgot it meant that P = 0 thanks
October 6, 2013

Pre-Calculus
The function is P=−11x^2+346.5x−2612.5
October 6, 2013

Pre-Calculus
The profit in dollars in producing x items of some commodity is given by the equation P=−11x2+346.5x−2612.5. How many items should be produced to break even?(If there are two break-even points, then enter the smaller value of x. Your solution may not be an integer...
October 6, 2013

Pre-Calculus
thanks I figured out what I did wrong
October 6, 2013

Pre-Calculus
Find the unknown in the following equation. If there are more than one solution, then separate the solutions with a comma. (−8y−4)^2+10=14 y=? I keep on getting y=-0.5, is that correct?
October 6, 2013

Pre-Calculus
thanks!
October 6, 2013

Pre-Calculus
The Hotel Bellville has 400 rooms. Currently the hotel is filled . The daily rental is $ 250 per room. For every $ 14 increase in rent the demand for rooms decreases by 5 rooms. Let x = the number of $ 14 increases that can be made. What should x be so as to maximize the ...
October 6, 2013

Pre-Calculus
thanks
September 30, 2013

Pre-Calculus
oh ok. But if I wanted to find how long it takes the ball to come back to the ground then I would have to factor it right?
September 30, 2013

Pre-Calculus
Sorry, the equation is −16t^2+72t+364
September 30, 2013

Pre-Calculus
A ball is thrown up at the edge of a 364 foot cliff. The ball is thrown up with an initial velocity of 72 feet per second. Its height measured in feet is given in terms of time t, measured in seconds by the equation h=−16t2+72t+364. How high will the ball go? To get how ...
September 30, 2013

Pre-Calculus
So the answer is C(x)= 2574 + 3x?
September 30, 2013

Pre-Calculus
I solved that and got C(x) = 2580 + 3x, but apparently it's still not the right answer...
September 30, 2013

Pre-Calculus
A local photocopying store advertises as follows. " We charge 14 cents per copy for 150 copies or less, 6 cents per copy for each copy over 150 but less than 230, and 3 cents per copy for each copy 230 and above. " Let x be the number of copies ordered and C(x) be ...
September 30, 2013

Pre-Calculus
Then what would the cost be for 150<x<230? I don't think there's a fixed cost for this either, but I don't think it'd be correct to write C(x) = 6x.
September 30, 2013

Pre-Calculus
A local photocopying store advertises as follows. " We charge 14 cents per copy for 150 copies or less,6 cents per copy for each copy over 150 but less than 230, and 3 cents per copy for each copy 230 and above. " Let x be the number of copies ordered and C(x) be the...
September 30, 2013

Pre-Calculus
Oh, ok, so it's not equivalent. I get it now. It is 2.2. Thanks!
September 28, 2013

Pre-Calculus
Wait, Steve, I think that what you wrote: A(t) = 11000 - (11000-10995.60)*t/4.4 is equivalent to what I wrote: A(t) = -4.4t + 11,000 but when I solve mine, why do I keep on getting 0.5 instead of 2.2?
September 28, 2013

Pre-Calculus
A machine worth $ 11000 new and having a scrap value of $ 10995.6 is to be depreciated over a 4.4 -year life. Find the function that describes straight line depreciation for this situation. At what time will the machine be worth $ 10997.8 according to this model? So I know ...
September 28, 2013

Pre-Calculus
Nevermind, I figured it out, it's $63.
September 28, 2013

Pre-Calculus
If a manufacturer has fixed costs of $ 300 , a cost per item for production of $ 60 , and expects to sell at least 100 items, how should he set the selling price to guarantee breaking even? I set up the cost function by writing 300 + 60x, but I don't know what to do next...
September 28, 2013

Math
Describe the steps for simplifying the expression 3a^3 + 4 - 4a - 2a^3 + 6 + 12a - b^3. Be specific and be sure to include the meaning of like terms in your explanation.
September 25, 2013

math
(t-r)^2(t-r)^2(t-r)^2
September 19, 2013

Financial management
how do I solve for x in the following equation: 1.2 ($1,364,994,000 + x) = $1, 807,626,000 + x
September 14, 2013

Physics
Two identical capacitors store different amounts of energy: capacitor A stores 2.5 x 10-3 J, and capacitor B stores 2.8 x 10-4 J. The voltage across the plates of capacitor B is 11 V. Find the voltage across the plates of capacitor A.
September 12, 2013

physics
A catapult launches a test rocket vertically upward from a well, giving the rocket an initial speed of 79.0 m/s at ground level. The engines then fire, and the rocket accelerates upward at 3.90 m/s2 until it reaches an altitude of 980 m. At that point its engines fail, and the...
August 25, 2013

MATH
Ned’s Sheds purchases building materials from Timbertown Lumber for $3,700 with terms of 4/15, n/30. The invoice is dated October 17. Ned’s decides to send in a $2,000 partial payment. By what date must the partial payment be sent to take advantage of the cash ...
August 18, 2013

Physics
An object with an initial velocity of 5 m/s has a constant acceleration of 2 m/s^2. When its speed is 15 m/s how far has it traveled?
July 24, 2013

Philosophy
Identify a current event or contemporary social issue that involves ethical values.
July 16, 2013

Chemistry
Net ionic equations for: Br- + AgNO3 CO3 + AgNO3 Cl-+ AgNO3 I + AgNO3 PO4^-3 + AgNO3 SO4^-2 + AgNO3 S^-2 + AgNO3 They all formed ppt,but I don't know where to go from here. Even a couple to get me started would be greatly appreciated!
July 14, 2013

Chemistry
Are these reactions Exothermic or Endothermic? How do I know? 1.) Mg(OH)2(s)<==>Mg+2(aq) + 2OH-(aq) Saw solution lighten from medium pink to very light when heated in hot water bath. (It had phenolphthalein drop for indicator.) 2.) HSO4-(aq)+ H2O(l)<==>H3O+(aq)+SO4...
July 11, 2013

Aftercare school curriculum
Most common early childhood program in the united states
July 2, 2013

Chemistry
Do I solve this by multiplying 1.8645 by 1.14??The equation of your calibration curve from a spectrophotometry experiment was y = 1.8645x. Assuming your calibration curve is set up exactly like it was in lab (concentration in mM on the x axis and absorbance on the y axis), ...
June 25, 2013

Physics
A seesaw is 4 meters long and is pivoted in the middle. There is a 350 N child on the left end. Where will a 540 N person have to sit to balance the seesaw?
June 22, 2013

Spanish
La palabra escondida es unscramble these letters sneauodsyma
May 28, 2013

math
7/4 as f/15 therefore 4 times 3.75 = 15 then 7 times 3.75 = 26.25 Answer: 26.25 is the force needed to stretch 15 inches which is m.
May 27, 2013

math
3/5
May 27, 2013

statistics
My mean is 175.5 My standard deviation is=90.57 Sample=25 Formula to be used: P(X>190)=P((X-mean)/s sqrt of my sample is = 5 (Which is the square root of 25.) (190-175.5) / 90.57/5) 14.5/18.114 calculator says 0....
May 27, 2013

statistics
Facebook reports that the average number of Facebook friends worldwide is 175.5 with a standard deviation of 90.57. If you were to take a sample of 25 students, what is the probability that the mean number Facebook friends in the sample will be 190 friends or more?
May 27, 2013

health care
How does the system of health care provision in the U.S. support goals of public health? Provide an example.
May 25, 2013

MATH - PLEASE HELP
A biased coin is tossed 5 times where p(t) = .6. determine the probability that if you have 2 tails, you have 3 tails.
May 25, 2013

Math
thanks so much!
May 25, 2013

Math
A biased coin is tossed 5 times where p(t) = .6. determine the probability that if you have 2 tails, you have 3 tails.
May 25, 2013

Math
Edna has scored in 80% of the games she's played.What is the probability she woulds score a goal in at least 7 out of her 8 games. P (if she scored in 3 or 4 games, what is the probability that she scores in exactly 4).?
May 24, 2013

Microeconomy
uppose the demand for these jets is given by the equation: P = 3000 - Q, where Q denotes the quantity of jets, and P denotes its price. So that the marginal revenue facing the firm is: MR = 3000 - 2Q. The marginal cost of Lockheed Martin is given by the equation: MC(Q) = 2Q ...
May 24, 2013

Math
Fantasia Florist Shop purchases an order of imported roses with a list price of $2,375 less trade discounts of 15/20/20. What is the dollar amount of the trade discount? Answer: 1306.25 4. Using your answer to the question above, what is the net dollar amount of that rose ...
May 20, 2013

Math
What is the net price factor for trade discounts of 25/15/10? Answer: .57375 Just checking my homework answers
May 20, 2013

Math
Natureland Garden Center buys lawn mowers that list for $679.95 less a 30% trade discount. What is the dollar amount of the trade discount? Answer: 203.99 What is the net price of each Natureland Garden Center lawn mower? Answer: 475.96 Just want to make sure my answer is ...
May 20, 2013

Math
By what percent is a 100-watt light bulb brighter than a 60-watt light bulb? Round to the nearest tenth. 40/60 = 2/3 = 2 ÷ 3 = 0.666667 0.666667 x 100 = 66.6667% Answer: 66.7% Is this correct?
May 13, 2013

Math
What is the portion if the base is 900 and the rate is 12¾ %? P=RxB P=12.75x900 P=11,475 Is this correct?
May 13, 2013

Math
Sunshine Honda sold 112 cars this month. If that is 40% greater than last month, how many cars were sold last month? x=112*100/140 x= 80 Answer: 80 Is this correct?
May 13, 2013

Math
Michael Reeves, an ice cream vendor, pays $17.50 for a five-gallon container of premium ice cream. From this quantity he sells 80 scoops at $0.90 per scoop. If he sold smaller scoops, he could sell 98 scoops from the same container; however, he could charge only $0.80 per ...
May 13, 2013

Math
By what percent is a 100-watt light bulb brighter than a 60-watt light bulb? I'm not sure the equation to use to solve this one.
May 13, 2013

Math
Sorry Ms. Sue. I put your name in by mistake.
May 13, 2013

Math
After a 15% pay raise, Scott Walker now earns $27,600. What was his salary before the raise? Answer: 27600=.15x*27600 x=4140 27600-4140=23,460 Is my answer correct?
May 13, 2013

Math
A letter carrier can deliver mail to 112 homes per hour by walking and 168 homes per hour by driving. By what percent is productivity increased by driving? Answer: 56% Is my answer correct?
May 13, 2013

Math
If 453 runners out of 620 completed a marathon, what percent of the runners finished the race? (Round percent to the nearest tenth.) Answer: 453/620= .731 Changing to percent 73.1% Is this correct?
May 13, 2013

Math
Thanks!
May 10, 2013

Math
What is the exact answer to cos^2x - sin^2x = 0 for between 0 and 2pi? I got x = pi/4 and x = 5pi/4. But the answer key says there are two additional answers which are 3pi/4 and 7pi/4. I don't know how to get these. Any help is much appreciated!
May 10, 2013

Math
Problem Solving Work Backward The test that Keyshawn's class took finished at 10:30 a.m. The first part of the test took 30 minutes. There was a 15 minute break. The second part of the test also took 30 minutes. At what time did the test start?
May 2, 2013

Math
Problem Solving: Work Backward At 12 noon, Leslie recorded the temperature as 56 degree Fahrenheit. The temperature had increased by 8 degree Fahrenheit from 10 a.m. The temperature at 8 a.m. was 2 degree Fahrenheit warmer than it was at 10 a.m. What was the temperature at 8 a.m.
May 2, 2013

Math
I'm having a hard time coming up with the right equation to solve this one. E-Z Stop Fast Gas sold $10,957 worth of gasoline yesterday. Regular grade sold for $2.30 a gallon and premium grade sold for $2.55 a gallon. If the station sold 420 more gallons of regular than of ...
May 1, 2013

Math
Is this the correct numerical expression for 15 less than one-ninth of P? 15-1/9 P
May 1, 2013

Math
A machine produces a voltage in the following formula V(t) = 300cos(10(pi)x). X is the time in seconds. Graph the function with the restriction 0 < X < 1
April 28, 2013

accounting
Phil Phoenix is paid monthly. For the month of January of the current year, he earned a total of $8,288. The FICA tax rate for social security is 6.2% and the FICA tax rate for Medicare is 1.45%. The FUTA tax rate is 0.8%, and the SUTA tax rate is 5.4%. Both unemployment taxes...
April 28, 2013

AP tatistics
A horticulturist wishes to estimate the mean growth of seedlings in a large timber plot last year. A random sample of n = 100 seedlings is selected and the one-year growth for each is measured. The sample yields = 5.62 cm. The known standard deviation for this popualtiopn is ...
April 21, 2013

Science
Make a solutions by dissolving 4 lbs of sulfur dioxide in 100 lbs of water then heat to 30 degress C. what is the partial pressure of the sulfur dioxide over the solution specified?
April 13, 2013

Math
A scientist is mixing a chemical solution for an experiment. The solution contains 3/8 ounce of a chemical and 1/6 ounce saline solution. What is the unit rate of chemical to saline solution?
April 5, 2013

Math Statistics
The annual per capita consumption of fresh apples (in pounds) in a nearby state can be approximated by a normal distribution, with a mean of 15.9 pounds and a standard deviation of 4.2 pounds. (a) What is the smallest annual per capita consumption of apples that can be in the ...
April 1, 2013

math
10%
March 31, 2013

statistics
I need a estimate within $25, the true average of amount of postage a company spends each year. If I want to be 98% confident, how large a sample is necessary? The standard deviation is known to be $80
March 29, 2013

statistics
The standard deviation of the diameter of 18 baseballs was 0.29cm. Find the 95% confidence interval of the true standard deviation of the diameters of the baseballs. Do you think the manufacturing process should be checked for inconsistency?
March 28, 2013

statistics
confidence intervals: A researcher is interested in estimating the average salary of teachers in a large school district. She wants to be 95% confident that her estimate is correct. If the standard deviation is $1050, how large a sample is needed to be accurate within $200.
March 28, 2013

Chemistry
Enough of a monoprotic acid is dissolved in water to produce a 0.0190 M solution. The pH of the resulting solution is 2.33. Calculate the Ka for the acid.
March 26, 2013

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