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richard1234 answered: 5385 problems
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expressions/488760: Please help me with this Algebra problem.
Perform the indicated opperation and, simplify if possible. Thank you.
1/11 + (- 5/6)
1 solutions
Answer 333441 by richard1234(5390)   on 2011-08-30 21:30:16 (Show Source):
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test/488289: Prove the sum of two rational numbers is rational, using real analysis
1 solutions
Answer 333389 by richard1234(5390) on 2011-08-30 17:13:30 (Show Source):
You can put this solution on YOUR website!Real analysis would assert that the rational numbers form an ordered field, and that the axiom of closure is satisfied (e.g. the sum of two rational numbers is another rational number in the set).
It is also very easy to prove this without any sort of analysis. Just let a/b and c/d be your two rational numbers, and  , also a rational number.
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Polynomials-and-rational-expressions/488476: Essay: Show all work. A school designer wants to create a whiteboard with the optimal dimensions to enhance learning. It is determined that if one side of the whiteboard is x + 5y inches, the other side should be x^2+3xy-4y^2 inches. Write an algebraic expression for the area of such a whiteboard, simplify it, and include correct units with your solution.
1 solutions
Answer 333388 by richard1234(5390) on 2011-08-30 17:07:44 (Show Source):
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Probability-and-statistics/488401: can someone please help me?
essay show all work. a simple dartboard has three areas, the main board has a radious of 9in, there is a circle with a radious of 6 in, and the bullseye has a radious of 2 in, what is the probability of a random dart landing inside the bullseye? round to the nearest thousandth.
1 solutions
Answer 333385 by richard1234(5390) on 2011-08-30 16:57:06 (Show Source):
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Rational-functions/488239: Suppose you are an event coordinator for a large performance theater. One of the hottest new Broadway musicals has started to tour and your city is the first stop on the tour. You need to supply information about projected ticket sales to the box office manager. The box office manager uses this information to anticipate staffing needs until the tickets sell out. You provide the manager with a quadratic equation that models the expected number of ticket sales for each day x. ( is the day tickets go on sale).
a. Does the graph of this equation open up or down? How did you determine this?
b. Describe what happens to the tickets sales as time passes.
c. Use the quadratic equation to determine the last day that tickets will be sold.
Note. Write your answer in terms of the number of days after ticket sales begin.
d. Will tickets peak or be at a low during the middle of the sale? How do you know?
e. After how many days will the peak or low occur?
f. How many tickets will be sold on the day when the peak or low occurs?
g. What is the point of the vertex? How does this number relate to your answers in parts e. and f?
h. How many solutions are there to the equation ? How do you know?
i. What do the solutions represent? Is there a solution that does not make sense? If so, in what ways does the solution not make sense?
1 solutions
Answer 333325 by richard1234(5390) on 2011-08-30 09:35:29 (Show Source):
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test/487739: In substitution is your final answer a point?
1 solutions
Answer 333296 by richard1234(5390) on 2011-08-30 01:16:07 (Show Source):
You can put this solution on YOUR website!I have to make the intuitive guess that you are referring to solving a system of linear equations by substitution. If this is so, the answer is yes (most of the time), because a system of two linear equations of two variables will usually have one ordered pair as a solution. Graphically, all this is saying that two lines on the same plane meet at a point. The exceptions are when the lines are parallel (no solutions), or the lines are the same (infinitely many solutions).
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Sequences-and-series/487743: Respected Sir ,
Please help me to solve this question, I will be very grateful for your help
If the AM and HM for two numbers are 5 and 3.2 respectively then the GM will be
As the answer given is : 4.00
Please help me to simplify this !!!
1 solutions
Answer 333295 by richard1234(5390) on 2011-08-30 01:13:59 (Show Source):
You can put this solution on YOUR website!Let a and b be two numbers with
 , and
The second equation becomes
 , replace a+b with 10 to get
The geometric mean of a and b is  , or  .
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Angles/488022: An angle is three more than twice its compliment. what is the angle?
1 solutions
Answer 333292 by richard1234(5390) on 2011-08-30 01:07:59 (Show Source):
You can put this solution on YOUR website!Let the angle be x. Then,
x = 3 + 2(90-x) (converting into an equation)
x = 3 + 180 - 2x
3x = 183 --> x = 61 (degrees)
Also, it's spelled "complement." "Compliment" means to praise someone.
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Probability-and-statistics/487927: 3. A technique used to arrive at the regression equation by minimizing the sum of the squares of the vertical differences between the actual Y values and the predicted Y values is known as the ______________.
1 solutions
Answer 333291 by richard1234(5390) on 2011-08-30 01:05:31 (Show Source):
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Complex_Numbers/488110: (-4+6i)(-3+7i)
1 solutions
Answer 333290 by richard1234(5390) on 2011-08-30 01:01:15 (Show Source):
You can put this solution on YOUR website!The other tutor is referring to it as FOIL (instead of foil) because FOIL is an acronym for "first, outer, inner, last," an order in which you can multiply two binomials. For example,
(-4+6i)(-3+7i) = (-4)(-3) + (-4)(7i) + (6i)(-3) + (6i)(7i)
= 12 - 28i - 18i - 42
= -30 - 46i
The textbook writers must have come up with FOIL pretty recently. I don't remember learning that acronym in my algebra class...and I'm a senior in HS so it's only been 5 or so years since I learned algebra.
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Quadratic_Equations/487716: I need help!
1. Suppose you are an event coordinator for a large performance theater. One of the hottest new Broadway musicals has started to tour and your city is the first stop on the tour. You need to supply information about projected ticket sales to the box office manager. The box office manager uses this information to anticipate staffing needs until the tickets sell out. You provide the manager with a quadratic equation that models the expected number of ticket sales for each day x. ( is the day tickets go on sale).
Tickets=-0.2x^2+12x+11=0
a. Does the graph of this equation open up or down? How did you determine this?
b. Describe what happens to the tickets sales as time passes.
c. Use the quadratic equation to determine the last day that tickets will be sold.
Note. Write your answer in terms of the number of days after ticket sales begin.
d. Will tickets peak or be at a low during the middle of the sale? How do you know?
e. After how many days will the peak or low occur?
f. How many tickets will be sold on the day when the peak or low occurs?
g. What is the point of the vertex? How does this number relate to your answers in parts e. and f?
h. How many solutions are there to the equation -0.2x^2+12x+11=0
? How do you know?
i. What do the solutions represent? Is there a solution that does not make sense? If so, in what ways does the solution not make sense?
1 solutions
Answer 333288 by richard1234(5390) on 2011-08-30 00:56:46 (Show Source):
You can put this solution on YOUR website!Ah, yes, one of the extremely over-used problems that has 50 parts and that every mathematics textbook is eventually going to have.
Anyway, instead of writing out an entire solution for each part, you might want to Google this question, because I see it all the time on algebra.com. Here is a past solution written by stanbon, one of our algebra.com tutors:
http://www.algebra.com/algebra/homework/quadratic/Quadratic_Equations.faq.question.150916.html
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Travel_Word_Problems/488032: Need your help... Don't understand, how to figure this out....
the speed of a bicycle from 10 km/h to 15 km/h over the course of 1 hr. Calculate the bicycle's acceleration
1 solutions
Answer 333287 by richard1234(5390) on 2011-08-30 00:52:50 (Show Source):
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Geometry_proofs/488188: I'm having trouble with the following problem, apparently in solving this solution I was told that the proof was oversimplified and more information was needed. I'm at a lost, any help you can give would be greatly appreciated.
Thank you.
Given: Triangle BAD is congruent to Triangle CAD
AD is perpendicular to BC
Prove: Triangle ABC is isosceles
My solution:
Triangle BAD is congruent to Triangle CAD (statement) Given (reason)
AD is perpendicular to BC (statement) Given (reason)
BA is congruent to AC (statement) Corresponding parts of congruent triangles (reason)
1 solutions
Answer 333286 by richard1234(5390) on 2011-08-30 00:50:45 (Show Source):
You can put this solution on YOUR website!
If we assume that the labeling in the problem ("Given triangle BAD is congruent to triangle CAD") is correct, then right away we can claim BA = CA and triangle ABC is isosceles (you might want to say BA = CA --> ABC is isosceles in your proof).
If the labeling is incorrect (e.g. triangle BAD is actually congruent to triangle CDA") then that is a mistake on the textbook. Just make sure you also label your points correctly, matching corresponding ones next to each other.
Either way, you would want to specify that BA = CA implies that triangle ABC is isosceles.
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decimal-numbers/488014: the surface area of the moon is 37,900,000 square kilometers, which has larger surface area?
1 solutions
Answer 333285 by richard1234(5390) on 2011-08-30 00:39:28 (Show Source):
You can put this solution on YOUR website!The question "Which has larger surface area?" implies you have to choose between two or more objects or things. You only posted one "thing," the surface area of the moon. We need another object to compare it to. Post your entire question next time.
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Functions/488151: find the equation that describes {(2,5),(1,2),(0,1),(-1,2),(-2,5)}
1 solutions
Answer 333283 by richard1234(5390) on 2011-08-30 00:36:18 (Show Source):
You can put this solution on YOUR website!First, write your ordered pairs in order by x-coordinate.
(-2,5)
(-1,2)
(0,1)
(1,2)
(2,5)
While these ordered pairs do not have a unique solution, we can find a continuous function that models this. The function appears to be symmetric about x = 0, and by noticing a pattern we can tell that y = x^2 + 1 appears to be a solution.
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test/488093: Pre-Algebra:Algebra expression
Q1:two inches shorter than Kathryn's height.
Q2:the quotient of some number and thirteen
Q3:Some number added to seventeen
Q4:six centimeters shorter than the length of the pencil
Q5:three pounds lighter than Adlai's weight
Q6:the difference of some number and eighteen
Q7:three dollars more than the cost of a ticket
Q8:eight more than the product of a number and four
Q9:half as many pieces of candy
Q10:twice as long the length of the string
1 solutions
Answer 333282 by richard1234(5390) on 2011-08-30 00:33:41 (Show Source):
You can put this solution on YOUR website!You want to define a variable and be able to manipulate that variable to whatever the question is asking you.
For Q1, let k be Kathryn's height in inches. Then k-2 would be two inches shorter than Kathryn's height.
Or for Q2, let x be the number. "Quotient" implies you are dividing, and the quotient of a number and 13 is assumed to be x/13.
Try the others the same way.
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decimal-numbers/488017: DESCRIBE TWO METHODS FOR DETERMINING WHERE TO PLACE THE DECIMAL POINT IN THE PRODUCT OF TWO DECIMALS?
1 solutions
Answer 333281 by richard1234(5390) on 2011-08-30 00:31:28 (Show Source):
You can put this solution on YOUR website!Method #1 is when you are multiplying two decimal numbers, count how many digits are after the decimal point for each number. For example, (36.58)(2.4), there are two digits after the decimal point in 36.58 and one digit for 2.4. Add these to get three, so after you multiply, move the decimal point three positions to the left to compensate.
Method #2 is intuition (because 36.58 times 2.4 can't equal 877.92 can it?).
There's really only one method (and maybe variations) to find where to put the decimal point, though.
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