Friday

March 6, 2015

March 6, 2015

Total # Posts: 1,289

**Pre-Calculus**

Solve the equation 2x + 5y - 3z = -1. Write the general solution as a matrix equation. I did some guessing and ended up getting this much: [x]= [-1/2 _ _ ] X [1] [y]= [ 0 1 0 ] X [s] [z]= [ 0 0 1 ] X [t] however I still can't figure out the last two values in the first row
*December 6, 2013*

**Pre-Calculus**

I still don't really understand how to do it... I did some guessing and ended up getting this much: [x] [-1/2 _ _] [1] [y]= [0 1 0] X [s] [z] [0 0 1] [t] however I still can't figure out the last two values in the first row.
*December 6, 2013*

**Pre-Calculus**

[x] [...] [1] [y]= [...] X [s] [z] [...] [t] to align it better I put dots in the blanks...and I think s and t are free variables that be be any real number
*December 6, 2013*

**Pre-Calculus**

Solve the equation 2x + 5y - 3z = -1. Write the general solution as a matrix equation. [x] [ ] [1] [y]= [ ] X [s] [z] [ ] [t] I'm supposed to fill in that blank in the middle, but I don't understand how to solve this if I'm only given one equation. please explain
*December 6, 2013*

**Pre-Calculus**

if not, then can you show me how to do this with the substitution method or something?
*December 4, 2013*

**Pre-Calculus**

Consider the chemical reaction aC2H6 + bCO2 + cH2O → dC2H5OH, where a, b, c, and d are unknown positive integers.? The reaction must be balanced; that is, the number of atoms of each element must be the same before and after the reaction. For example, because the number ...
*December 4, 2013*

**Pre-Calculus**

wow that was a silly mistake I didn't see the x next to 500 and thought I could just subtract it from 1000 thank you!
*November 20, 2013*

**Pre-Calculus**

A piece of equipment has cost function C(x)=50x^2 + 1000 and its revenue function is R(x)= 500x - x^2, where x is in thousands of items. What is the least number of items that must be sold in order to break even? 50x^2 + 1000 = 500x - x^2 50x^2 + x^2 + 500= 0 51x^2 + 500 = 0 ...
*November 20, 2013*

**Pre-Calculus**

Wow, I didn't realize that finding (x-2) was already finding the equation of the line. Thanks!
*November 19, 2013*

**Pre-Calculus**

The graph of f(x)= (x^2 - 11x + 18)/(x-9) consists of a line and a hole. Find the equation of the line and the coordinates of the hole. I really have no idea how to do this. I tried factoring it and ended up with (x-2), but I don't know how that helps me. please help
*November 19, 2013*

**Pre-Calculus**

oh yeah thanks I forgot that the reciprocal had to be negative
*November 19, 2013*

**Pre-Calculus**

What is the equation of the line passing through (4, 2) and perpendicular to the line passing through the points (9,7) and (11,4)? Here's what I did: (7-4)/(9-11) = -3/2 y-2= (-2/3)(x-4) y-2=(-2x/3) + (8/3) y = (-2x/3) + 14/3 but the answer key says that it's y=(2x/3...
*November 19, 2013*

**Pre-Calculus**

thanks...though I asked for (-3,-1).
*November 17, 2013*

**Pre-Calculus**

Find the slope of the tangent line to the curve 2(x^2+y^2)^2=25(x^2−y^2) at the point (−3,−1)? Here's what I did: 2(x^4 + y^4) = 25(x^2-y^2) 2x^4 + 2y^4 = 25x^2 - 25y^2 8x^3 + 8y^3(dy/dx) = 50x - 50y(dy/dx) d/dx(8y^3 + 50y) = 50x - 8x^3 d/dx = (50x-8x^3...
*November 17, 2013*

**Pre-Calculus**

thanks
*November 14, 2013*

**Pre-Calculus**

no it's actually 1x and 1xy. It's not division.
*November 14, 2013*

**Pre-Calculus**

Find the slope of the tangent line to the curve √(1x+2y) + √(1xy) = 8.24 at the point (2,8)? I know you have to use implicit differentiation, but the radicals keep making me mess up algebraically. Is the changing the radicals to exponents the fastest way? please ...
*November 14, 2013*

**Pre-Calculus**

nevermind I made a mistake it's p(x)=-1x/10 + 465
*November 13, 2013*

**Pre-Calculus**

A manufacture has been selling 1050 television sets a week at 360 dollars each. A market survey indicates that for each 20 -dollar rebate offered to a buyer, the number of sets sold will increase by 200 per week. p(x)=1x/10 + 465 How large of a rebate should the company offer ...
*November 13, 2013*

**Pre-Calculus**

Thank you all so much!
*November 12, 2013*

**Pre-Calculus**

When you do implicit differentiation, how does D = √(x^2 + 8x + 12) turn into dD/dt = [(x + 4)(dx/dt)]/√(x^2 + 8x + 12)? please explain...I don't even understand where the (x+4) comes from. D means distance, but that's irrelevant
*November 12, 2013*

**Physics**

laf is standing on a sheet of ice that covers the football stadium parking lot in Buffalo, New York; there is negligible friction between his feet and the ice. A friend throws Olaf a ball of mass 0.400kg that is traveling horizontally at 11.5m/s . Olaf's mass is 65.2kg. If...
*November 12, 2013*

**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*

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