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Numbers_Word_Problems/252619: I am checking my sons math.
Find four consecutive even integers such that 6 time the sum of the first and second is 8 more than 10 times the fourth.
Rob Dewey...Mitchell's Dad.
1 solutions

Answer 184637 by jim_thompson5910(28598) About Me  on 2009-12-29 18:43:55 (Show Source):
You can put this solution on YOUR website!
Consecutive even integers follow the form: x, x+2, x+4, x+6, etc...

So because "6 time the sum of the first and second is 8 more than 10 times the fourth", this translates to 6%28x%2Bx%2B2%29=10%28x%2B6%29%2B8


6%28x%2Bx%2B2%29=10%28x%2B6%29%2B8 Start with the given equation.


6x%2B6x%2B12=10x%2B60%2B8 Distribute.


12x%2B12=10x%2B60%2B8 Combine like terms on the left side.


12x%2B12=10x%2B68 Combine like terms on the right side.


12x=10x%2B68-12 Subtract 12 from both sides.


12x-10x=68-12 Subtract 10x from both sides.


2x=68-12 Combine like terms on the left side.


2x=56 Combine like terms on the right side.


x=%2856%29%2F%282%29 Divide both sides by 2 to isolate x.


x=28 Reduce.


----------------------------------------------------------------------

Answer:

So the solution is x=28 which means that the four consecutive even integers are

x = 28
x+2 = 30
x+4 = 32
x+6 = 34


Trigonometry-basics/252605: The height of the ocean at the dock is modeled by the function, h= 3sin(pi*t/4) +5 where h is measured in feet and t is the time in hours. If t=0 refers to 12:00 a.m., what is the height of the ocean at 10:00 a.m.?
find the exact value of the vertical asymptotes for 0<=x<=pi for the function y=cot(3x)
if sin(x)= -3/5 with x in the quadrant 4, find the sec(x)
Thanks so much!!
1 solutions

Answer 184615 by jim_thompson5910(28598) About Me  on 2009-12-29 16:47:52 (Show Source):
You can put this solution on YOUR website!
I'll do the first two to get you going.

# 1

Since "t=0 refers to 12:00 a.m", this means that t=10 refers to 10:00 a.m. (just add 10 hours to 0)


h=3%2Asin%28pi%2At%2F4%29%2B5 Start with the given equation.


h=3%2Asin%28pi%2A10%2F4%29%2B5 Plug in t=10


h=3%2Asin%28pi%2A5%2F2%29%2B5 Reduce.


h=3%2Asin%285pi%2F2%29%2B5 Rearrange the terms


h=3%2Asin%285pi%2F2-2pi%29%2B5 Subtract 2pi from the argument (this is valid because you'll end up on a coterminal angle).


h=3%2Asin%28pi%2F2%29%2B5 Combine like terms.


h=3%2A1%2B5 Use the unit circle to evaluate the sine of pi%2F2 to get 1.


h=3%2B5 Multiply


h=8 Add


So the height of the ocean at 10:00 a.m. is 8 feet.


=================================================================

# 2

Remember that cot%28x%29=1%2Ftan%28x%29 and tan%28x%29=sin%28x%29%2Fcos%28x%29. So this means that cot%283x%29=1%2Ftan%283x%29=1%2F%28sin%283x%29%2Fcos%283x%29%29=cos%283x%29%2Fsin%283x%29 or in short, cot%283x%29=cos%283x%29%2Fsin%283x%29


To find the vertical asymptotes of cot%283x%29=cos%283x%29%2Fsin%283x%29, we'll set the denominator equal to zero and solve for 'x' (since division by zero is undefined).


sin%283x%29=0 Set the denominator equal to zero.


3x=arcsin%280%29 Take the arcsine of both sides.


x=0%2B2pi%2An or x=pi%2B2pi%2An Evaluate the arcsine of 0 to get x=0 or x=pi. Don't forget to add on multiples of 2pi to each solution.


x=%280%2B2pi%2An%29%2F3 or x=%28pi%2B2pi%2An%29%2F3 Divide both sides by 3 to isolate 'x' in each case.

As a shortcut, you can condense the solution to x=%281%2F3%29pi%2An where 'n' is an integer.


So if x=%281%2F3%29pi%2An, where 'n' is an integer, then sin%283x%29=0.


But since 0%3C=x%3C=pi, this means that we're only going to look at the solutions x=0 (for n=0), x=pi%2F3 (where n=1), x=2pi%2F3 (when n=2), and x=pi (when x=3). Note: any other solution is outside the interval 0%3C=x%3C=pi.


So the four vertical asymptotes of cot%283x%29 are x=0, x=pi%2F3, x=2pi%2F3, and x=pi


Linear-systems/252604: There are 35 tickets to be sold for the dance. The number of tickets sold to seniors must be four times the number of tickets sold to juniors.
please give me 2 linear equations and a solution.
A diamond today costs 10$ more than twice what it cost last year. The sum of the cost (last year and this year) is 2500$. What is the cost of last years diamond?
i need 2 linear equations and a solution for this question also.
THANK U SO MUCH!


1 solutions

Answer 184609 by jim_thompson5910(28598) About Me  on 2009-12-29 16:24:26 (Show Source):
You can put this solution on YOUR website!
# 1

Let s = # of senior tickets and j = # of junior tickets


Since there are 35 tickets in total, and we're assuming that only junior and senior tickets are sold, this means that j%2Bs=35. In other words, adding up the two totals will give you the grand total of 35.


Also, because "The number of tickets sold to seniors must be four times the number of tickets sold to juniors", we know that s=4j. In English, the number of senior tickets 's' is 4 times the number of junior tickets 'j'.


j%2Bs=35 Start with the first equation.


j%2B4j=35 Plug in s=4j


5j=35 Combine like terms on the left side.


j=%2835%29%2F%285%29 Divide both sides by 5 to isolate j.


j=7 Reduce.


So there are 7 junior tickets.


s=4j Go back to the second equation


s=4%2A7 Plug in j=7


s=28 Multiply


So there are 28 senior tickets.


As a check, take note that 28 is indeed 4 times 7 AND 28+7=35. So we've met our conditions.

======================================================================

# 2

Let t = cost of diamond today and y = cost of diamond last year


Since "A diamond today costs 10$ more than twice what it cost last year", we can say that t=2y%2B10 (ie double the cost from last year 'y' and add 10 to get the new cost today 't').


Also, because "The sum of the cost (last year and this year) is 2500$", we know that t%2By=2500 (just add up the two individual costs to get the grand total of $2500)


t%2By=2500 Start with the second equation.


2y%2B10%2By=2500 Plug in t=2y%2B10


3y%2B10=2500 Combine like terms on the left side.


3y=2500-10 Subtract 10 from both sides.


3y=2490 Combine like terms on the right side.


y=%282490%29%2F%283%29 Divide both sides by 3 to isolate y.


y=830 Reduce.


So the cost of the diamond last year was $830.


If you want to keep going then...


t=2y%2B10 Go back to the first equation


t=2%28830%29%2B10 Plug in y=830


t=1660%2B10 Multiply


t=1670 Add


So the cost of the diamond today is $1670.


Linear-systems/252597: Solve the following system of equations algebraically:
3x+2y=4
4x+3y=7
1 solutions

Answer 184601 by jim_thompson5910(28598) About Me  on 2009-12-29 15:58:03 (Show Source):
You can put this solution on YOUR website!

Start with the given system of equations:
system%283x%2B2y=4%2C4x%2B3y=7%29


3%283x%2B2y%29=3%284%29 Multiply the both sides of the first equation by 3.


9x%2B6y=12 Distribute and multiply.


-2%284x%2B3y%29=-2%287%29 Multiply the both sides of the second equation by -2.


-8x-6y=-14 Distribute and multiply.


So we have the new system of equations:
system%289x%2B6y=12%2C-8x-6y=-14%29


Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:


%289x%2B6y%29%2B%28-8x-6y%29=%2812%29%2B%28-14%29


%289x%2B-8x%29%2B%286y%2B-6y%29=12%2B-14 Group like terms.


x%2B0y=-2 Combine like terms.


x=-2 Simplify.


------------------------------------------------------------------


9x%2B6y=12 Now go back to the first equation.


9%28-2%29%2B6y=12 Plug in x=-2.


-18%2B6y=12 Multiply.


6y=12%2B18 Add 18 to both sides.


6y=30 Combine like terms on the right side.


y=%2830%29%2F%286%29 Divide both sides by 6 to isolate y.


y=5 Reduce.


So the solutions are x=-2 and y=5.


Which form the ordered pair .


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of 3x%2B2y=4 (red) and 4x%2B3y=7 (green)


Expressions-with-variables/252600: Solve for x:
2x over 3 +4 = x-5
1 solutions

Answer 184600 by jim_thompson5910(28598) About Me  on 2009-12-29 15:57:14 (Show Source):
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2x%2F3%2B4=x-5 Start with the given equation.


3%282x%2Fcross%283%29%2B4%29=3%28x-5%29 Multiply both sides by the LCD 3 to clear any fractions.


2x%2B12=3x-15 Distribute and multiply.


2x=3x-15-12 Subtract 12 from both sides.


2x-3x=-15-12 Subtract 3x from both sides.


-x=-15-12 Combine like terms on the left side.


-x=-27 Combine like terms on the right side.


x=%28-27%29%2F%28-1%29 Divide both sides by -1 to isolate x.


x=27 Reduce.


----------------------------------------------------------------------

Answer:

So the solution is x=27


Equations/252601: 9y+5-2y=2y+5-y+3 solve this equation

1 solutions

Answer 184598 by jim_thompson5910(28598) About Me  on 2009-12-29 15:55:54 (Show Source):
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9y%2B5-2y=2y%2B5-y%2B3 Start with the given equation.


7y%2B5=2y%2B5-y%2B3 Combine like terms on the left side.


7y%2B5=y%2B8 Combine like terms on the right side.


7y=y%2B8-5 Subtract 5 from both sides.


7y-y=8-5 Subtract y from both sides.


6y=8-5 Combine like terms on the left side.


6y=3 Combine like terms on the right side.


y=%283%29%2F%286%29 Divide both sides by 6 to isolate y.


y=1%2F2 Reduce.


----------------------------------------------------------------------

Answer:

So the solution is y=1%2F2 which approximates to y=0.5.


Expressions-with-variables/252593: 3x+6 over 4x+12 DIVIDED BY x^2-4 over x+3
1 solutions

Answer 184593 by jim_thompson5910(28598) About Me  on 2009-12-29 15:41:40 (Show Source):
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%28%283x%2B6%29%2F%284x%2B12%29%29%2F%28%28x%5E2-4%29%2F%28x%2B3%29%29 Start with the given expression.


%28%283x%2B6%29%2F%284x%2B12%29%29%28%28x%2B3%29%2F%28x%5E2-4%29%29 Multiply the first fraction %283x%2B6%29%2F%284x%2B12%29 by the reciprocal of the second fraction %28x%5E2-4%29%2F%28x%2B3%29.


%28%283%28x%2B2%29%29%2F%284x%2B12%29%29%28%28x%2B3%29%2F%28x%5E2-4%29%29 Factor 3x%2B6 to get 3%28x%2B2%29.


%28%283%28x%2B2%29%29%2F%284%28x%2B3%29%29%29%28%28x%2B3%29%2F%28x%5E2-4%29%29 Factor 4x%2B12 to get 4%28x%2B3%29.


%28%283%28x%2B2%29%29%2F%284%28x%2B3%29%29%29%28%28x%2B3%29%2F%28%28x-2%29%28x%2B2%29%29%29 Factor x%5E2-4 to get %28x-2%29%2A%28x%2B2%29.


%283%28x%2B2%29%28x%2B3%29%29%2F%284%28x%2B3%29%28x-2%29%28x%2B2%29%29 Combine the fractions.


Highlight the common terms.


Cancel out the common terms.


3%2F%284%28x-2%29%29 Simplify.


3%2F%284x-8%29 Distribute.


So %28%283x%2B6%29%2F%284x%2B12%29%29%2F%28%28x%5E2-4%29%2F%28x%2B3%29%29 simplifies to 3%2F%284x-8%29.


In other words, %28%283x%2B6%29%2F%284x%2B12%29%29%2F%28%28x%5E2-4%29%2F%28x%2B3%29%29=3%2F%284x-8%29


Inequalities/252591: what do the word at most means?

1 solutions

Answer 184584 by jim_thompson5910(28598) About Me  on 2009-12-29 15:20:17 (Show Source):
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The phrase "at most" means that it is the largest value a variable can take on. When I say: "I have 'at most' 10 dollars", this means that the maximum amount of money I have is $10. I could have less than $10, but the most I have is $10. Algebraically, if 'x' is the amount of money I have, then this translates to x%3C=10


Numbers_Word_Problems/252512: when N is divided by 5, the remainder is 3. what is the remainder when 7N is divided by 5?
1 solutions

Answer 184486 by jim_thompson5910(28598) About Me  on 2009-12-29 00:42:39 (Show Source):
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Since dividing N by 5 gives a remainder of 3, this means that N%2F5=q%2B3%2F5 where 'q' is the quotient (which is some whole number). Multiplying everything by 5 gets us N=5q%2B3


So 7N=7%285q%2B3%29=35q%2B21. If we divide 7N by 5, we then get 7N%2F5=%2835q%2B21%29%2F5=%2835q%29%2F5%2B21%2F5=7q%2B21%2F5. In other words, 7N%2F5=7q%2B21%2F5. The remainder is 21%2F5, but it's too big which means that we need to break it up. So 21%2F5=%2820%2B1%29%2F5=20%2F5%2B1%2F5=4%2B1%2F5.

Since the fractional portion is 1%2F5, this tells us that the remainder is 1.

==================================
Answer:

So the remainder of dividing 7N by 5 is 1.


Note: Try some examples to give you an idea that it works.


Graphs/252515: I sure hope some one is feeling good this evening as im not good with this stuff and i need help with this problem. would you be so kind as to give me the steps and answer to it. Thank you so very much you all have been such great help to me.
b/7.8 = -2.15
again thank you for your help wiggles
1 solutions

Answer 184482 by jim_thompson5910(28598) About Me  on 2009-12-29 00:35:36 (Show Source):
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b%2F7.8=-2.15 Start with the given equation.


cross%287.8%29%28b%2Fcross%287.8%29%29=-2.15%2A7.18 Multiply both sides by 7.8 to isolate 'b'.


b=-16.77 Multiply -2.15 and 7.8 to get -16.77


So the solution is b=-16.77


Equations/252508: what multiplier should be used for each of the following equations to eliminate one unknown by subtraction?
3x-y=7
2x+7y=42
1 solutions

Answer 184481 by jim_thompson5910(28598) About Me  on 2009-12-29 00:28:58 (Show Source):
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The multiplier is 7 since this will change -y into -7y. Add this to 7y to get -7+7y=0y=0 which means that it cancels out.




Start with the given system of equations:
system%283x-y=7%2C2x%2B7y=42%29


7%283x-y%29=7%287%29 Multiply the both sides of the first equation by 7.


21x-7y=49 Distribute and multiply.


So we have the new system of equations:
system%2821x-7y=49%2C2x%2B7y=42%29


Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:


%2821x-7y%29%2B%282x%2B7y%29=%2849%29%2B%2842%29


%2821x%2B2x%29%2B%28-7y%2B7y%29=49%2B42 Group like terms.


23x%2B0y=91 Combine like terms.


23x=91 Simplify.


x=%2891%29%2F%2823%29 Divide both sides by 23 to isolate x.


------------------------------------------------------------------


21x-7y=49 Now go back to the first equation.


21%2891%2F23%29-7y=49 Plug in x=91%2F23.


1911%2F23-7y=49 Multiply.


23%281911%2Fcross%2823%29-7y%29=23%2849%29 Multiply both sides by the LCD 23 to clear any fractions.


1911-161y=1127 Distribute and multiply.


-161y=1127-1911 Subtract 1911 from both sides.


-161y=-784 Combine like terms on the right side.


y=%28-784%29%2F%28-161%29 Divide both sides by -161 to isolate y.


y=112%2F23 Reduce.


So the solutions are x=91%2F23 and y=112%2F23.


Which form the ordered pair .


This means that the system is consistent and independent.



Graphs/252509: HOW DO YOU GRAPH X=8 EXPLAIN IN DETAILS
1 solutions

Answer 184480 by jim_thompson5910(28598) About Me  on 2009-12-29 00:27:02 (Show Source):
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Simply draw a straight vertical line at x=8 to graph the equation x=8 like so:


Graph of x=8 (green vertical line)


Coordinate-system/252501: Solve the following system of equations algebraically and check:
2x + 3y = 11
5x - 2y = -20

1 solutions

Answer 184479 by jim_thompson5910(28598) About Me  on 2009-12-29 00:25:21 (Show Source):
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Start with the given system of equations:
system%282x%2B3y=11%2C5x-2y=-20%29


2%282x%2B3y%29=2%2811%29 Multiply the both sides of the first equation by 2.


4x%2B6y=22 Distribute and multiply.


3%285x-2y%29=3%28-20%29 Multiply the both sides of the second equation by 3.


15x-6y=-60 Distribute and multiply.


So we have the new system of equations:
system%284x%2B6y=22%2C15x-6y=-60%29


Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:


%284x%2B6y%29%2B%2815x-6y%29=%2822%29%2B%28-60%29


%284x%2B15x%29%2B%286y%2B-6y%29=22%2B-60 Group like terms.


19x%2B0y=-38 Combine like terms.


19x=-38 Simplify.


x=%28-38%29%2F%2819%29 Divide both sides by 19 to isolate x.


x=-2 Reduce.


------------------------------------------------------------------


4x%2B6y=22 Now go back to the first equation.


4%28-2%29%2B6y=22 Plug in x=-2.


-8%2B6y=22 Multiply.


6y=22%2B8 Add 8 to both sides.


6y=30 Combine like terms on the right side.


y=%2830%29%2F%286%29 Divide both sides by 6 to isolate y.


y=5 Reduce.


So the solutions are x=-2 and y=5.


Which form the ordered pair .


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of 2x%2B3y=11 (red) and 5x-2y=-20 (green)


Linear-systems/252498: Solve the following system of equations algebraically and check:
4x - 5y = 18
3x - 2y = 10

1 solutions

Answer 184478 by jim_thompson5910(28598) About Me  on 2009-12-29 00:24:12 (Show Source):
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Start with the given system of equations:
system%284x-5y=18%2C3x-2y=10%29


2%284x-5y%29=2%2818%29 Multiply the both sides of the first equation by 2.


8x-10y=36 Distribute and multiply.


-5%283x-2y%29=-5%2810%29 Multiply the both sides of the second equation by -5.


-15x%2B10y=-50 Distribute and multiply.


So we have the new system of equations:
system%288x-10y=36%2C-15x%2B10y=-50%29


Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:


%288x-10y%29%2B%28-15x%2B10y%29=%2836%29%2B%28-50%29


%288x%2B-15x%29%2B%28-10y%2B10y%29=36%2B-50 Group like terms.


-7x%2B0y=-14 Combine like terms.


-7x=-14 Simplify.


x=%28-14%29%2F%28-7%29 Divide both sides by -7 to isolate x.


x=2 Reduce.


------------------------------------------------------------------


8x-10y=36 Now go back to the first equation.


8%282%29-10y=36 Plug in x=2.


16-10y=36 Multiply.


-10y=36-16 Subtract 16 from both sides.


-10y=20 Combine like terms on the right side.


y=%2820%29%2F%28-10%29 Divide both sides by -10 to isolate y.


y=-2 Reduce.


So the solutions are x=2 and y=-2.


Which form the ordered pair .


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of 4x-5y=18 (red) and 3x-2y=10 (green)


Numbers_Word_Problems/252490: Grace has 16 jellybeans in her pocket. She has 8 red ones, 4 green ones, and 4 blue ones. What is the minimum number of jelly beans she must take out of her pocket to ensure that she has one of each color?
Could you please show me the set up and solution. Thank You
1 solutions

Answer 184454 by jim_thompson5910(28598) About Me  on 2009-12-28 19:04:15 (Show Source):
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Here's the worst case scenario:

First, she pulls out all 8 red jellybeans. So she has taken out all of the red jellybeans. Then she either pulls out 4 consecutive green or blue jellybeans (either one or the other but not both colors). So far, she's pulled out 8+4=12 jellybeans total. To ensure that she has taken at least one of each color, she'll need to pull out at least one more (either blue or green) since there is only one color left.


So in total, she'll have to pull out minimum of 8+4+1=13 jellybeans to ensure that she has at least one of each color.


Trigonometry-basics/252486: 2sin^2x+3cosx=3
1 solutions

Answer 184430 by jim_thompson5910(28598) About Me  on 2009-12-28 17:02:17 (Show Source):
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Hint: Recall that .


So this means that .


So plug in to get .


Now let and plug that in to get: .


At this point, we have a quadratic which can be solved by the quadratic formula. You'll get solutions in terms of 'z', so you'll need to remember to use to find the solutions in terms of 'x'. Let me know if you still need help.


Functions/252416: Q:State the domain and range for each of the following relations.State whether or not each relation is a function.
{(1,9),(2,12),(3,15),(4,22)}
1 solutions

Answer 184314 by jim_thompson5910(28598) About Me  on 2009-12-27 21:20:28 (Show Source):
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Domain: Set of all possible inputs (ie x values): {1, 2, 3, 4}

Range: Set of all possible outputs (ie y values): {9, 12, 15, 22}


Since each x value only maps to one (and ONLY one) y value, this means that this relation is a function.


Quadratic_Equations/249185: Solve equation by using the quadratic formula.
9x^2+5x-11=0

1 solutions

Answer 184313 by jim_thompson5910(28598) About Me  on 2009-12-27 21:17:55 (Show Source):
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9x%5E2%2B5x-11=0 Start with the given equation.


Notice that the quadratic 9x%5E2%2B5x-11 is in the form of Ax%5E2%2BBx%2BC where A=9, B=5, and C=-11


Let's use the quadratic formula to solve for "x":


x+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


x+=+%28-%285%29+%2B-+sqrt%28+%285%29%5E2-4%289%29%28-11%29+%29%29%2F%282%289%29%29 Plug in A=9, B=5, and C=-11


x+=+%28-5+%2B-+sqrt%28+25-4%289%29%28-11%29+%29%29%2F%282%289%29%29 Square 5 to get 25.


x+=+%28-5+%2B-+sqrt%28+25--396+%29%29%2F%282%289%29%29 Multiply 4%289%29%28-11%29 to get -396


x+=+%28-5+%2B-+sqrt%28+25%2B396+%29%29%2F%282%289%29%29 Rewrite sqrt%2825--396%29 as sqrt%2825%2B396%29


x+=+%28-5+%2B-+sqrt%28+421+%29%29%2F%282%289%29%29 Add 25 to 396 to get 421


x+=+%28-5+%2B-+sqrt%28+421+%29%29%2F%2818%29 Multiply 2 and 9 to get 18.


x+=+%28-5%2Bsqrt%28421%29%29%2F%2818%29 or x+=+%28-5-sqrt%28421%29%29%2F%2818%29 Break up the expression.


So the solutions are x+=+%28-5%2Bsqrt%28421%29%29%2F%2818%29 or x+=+%28-5-sqrt%28421%29%29%2F%2818%29


which approximate to x=0.862 or x=-1.418


Linear-equations/252412: I have been sitting here for hours trying to figure the following problems. I am working on Non-Linear Systems and have to solve the following systems. No matter how I work it I can't seem to come to a solution.
1) {7x-8y=24
{xy^2=1
2) {(x+1)^2 - (y-1)^2 = 20
{x^2 - (y+2)^2 - 24
Thank you - Lori
1 solutions

Answer 184310 by jim_thompson5910(28598) About Me  on 2009-12-27 20:42:42 (Show Source):
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Even though these are non-linear equations, we can still use substitution to solve them. I'll do the first one to get you started. If that doesn't help either repost or ask me.


# 1

xy%5E2=1 Start with the second equation.


x=1%2F%28y%5E2%29 Divide both sides by {{y^2}}} to isolate 'x'.


7x-8y=24 Move onto the first equation.


7%281%2F%28y%5E2%29%29-8y=24 Plug in x=1%2F%28y%5E2%29


7-8y%5E3=24y%5E2 Multiply EVERY term by the LCD y%5E2 to clear out the fractions.


-8y%5E3-24y%5E2%2B7=0 Get every term to the left side.


8y%5E3%2B24y%5E2-7=0 Multiply every term by -1.


Now use the rational root theorem to find that y=1%2F2 is a root to the polynomial equation above. In other words, if you plug in y=1%2F2 into 8y%5E3%2B24y%5E2-7, you will get 0. Because of this fact, this means that 2y-1 is a factor of 8y%5E3%2B24y%5E2-7


Now use polynomial long division to find that %288y%5E3%2B24y%5E2-7%29%2F%282y-1%29=4y%5E2%2B14y%2B7. So 8y%5E3%2B24y%5E2-7=%282y-1%29%284y%5E2%2B14y%2B7%29


This tells us that %282y-1%29%284y%5E2%2B14y%2B7%29=0. Since we know that 2y-1=0 gives a root of 1%2F2, we can ignore this equation. So the next step is to solve 4y%5E2%2B14y%2B7=0 for 'y'. Use the quadratic equation to find the next two solutions of y=%28-7%2Bsqrt%2821%29%29%2F4 or y=%28-7-sqrt%2821%29%29%2F4


So the three solutions in terms of 'y' are y=1%2F2, y=%28-7%2Bsqrt%2821%29%29%2F4 or y=%28-7-sqrt%2821%29%29%2F4


From here, plug each solution (in terms of 'y') into x=1%2F%28y%5E2%29 to find the corresponding solution in terms of 'x'.


I skipped a bit of steps (since they're a bit long and I'm out of time for now), so feel free to ask about any step.


Parallelograms/252408: If the following statement were to be proven using a coordinate proof which formulas would be used
the diagonals of a rhombus are congruent
(a) distance
(b) midpoint
(c) both
(d) the statement cant be proved
can you explain? thank you
1 solutions

Answer 184302 by jim_thompson5910(28598) About Me  on 2009-12-27 18:36:05 (Show Source):
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You would use the distance formula since this formula computes the distance between two points. If you know the coordinates of all four points, then you can find the distance from the opposite vertices. In other words, you can find the lengths of the diagonals using the distance formula. Since there is no point in using the midpoint formula, the answer is A)


Graphs/252406: Solve the following system of equations for x:
2x + y = 10
3x = y

1 solutions

Answer 184298 by jim_thompson5910(28598) About Me  on 2009-12-27 18:00:30 (Show Source):
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Note: Since 3x=y, this means that y=3x


2x+%2B+y+=+10 Start with the first equation.


2x+%2B+3x+=+10 Plug in y=3x


5x=10 Combine like terms on the left side.


x=%2810%29%2F%285%29 Divide both sides by 5 to isolate x.


x=2 Reduce.


----------------------------------------------------------------------

Answer:

So the solution is x=2


Note: if you need to find 'y' as well, simply plug x=2 into y=3x to find its value.


Proofs/251009: This stuff is crazy
O & I
O -> (S v G)
I -> ~G
We have to show S
1 solutions

Answer 184296 by jim_thompson5910(28598) About Me  on 2009-12-27 17:57:51 (Show Source):
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1.  O & I
2.  O -> (S v G)
3.  I -> ~G                / :. S
---------------------- 
4.  I & O                  1     Commutation
5.  O                      1     Simplification
6.  I                      4     Simplification
7.  ~G                     3,6   Modus Ponens
8.  S v G                  2,5   Modus Ponens
9.  S                      8,7   Disjunctive Syllogism


Travel_Word_Problems/252335: if a person hikes at approximately 3 km/hour, and has been hiking for 10 hours, how far have they hiked?
1 solutions

Answer 184193 by jim_thompson5910(28598) About Me  on 2009-12-26 20:24:04 (Show Source):
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Remember that the distance traveled (D) equals the rate (r) multiplied by the time (t). In other words, D = rt


D=rt Start with the given equation.


D=3%2A10 Plug in r=3 (the given speed) and t=10 (the given time)


D=30 Multiply


So if a person hikes for 10 hours at 3 km/hr, then they have gone 30 miles.


logarithm/252336: solve: ln(2x-1)=8
1 solutions

Answer 184192 by jim_thompson5910(28598) About Me  on 2009-12-26 20:21:58 (Show Source):
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ln%282x-1%29=8 Start with the given equation.


Recall that the equation ln%28x%29=y can be rewritten as x=e%5Ey


2x-1=e%5E8 Use the property shown above to convert the equation into exponential form.


2x=e%5E8%2B1 Add 1 to both sides.


x=%28e%5E8%2B1%29%2F2 Divide both sides by 2.


So the exact solution is x=%28e%5E8%2B1%29%2F2 which approximates to x=1490.97899352506


Probability-and-statistics/252330: Please help me solve this problem: In an exercise gym, 5 different people used a particular weight-training machine.
Name Weight
Mona 40
Sam 80
Tony 80
Alba 60
Peter 110
Use the data above to find the mean, median, mode. and range of the data. What effects does multiplication by a fixed number have on the mean, median, mode, and range of the data? Explain the reasoning for your answer.
- I already found the mean, median, mode, and range.
mean=74
median=80
mode=80
range=70

I just DON'T GET the question about the fixed number... PLEASE HELP ME AND EXPLAIN!!!

-thankyou! :)
1 solutions

Answer 184185 by jim_thompson5910(28598) About Me  on 2009-12-26 18:20:42 (Show Source):
You can put this solution on YOUR website!
Let k = some fixed number (ie a constant). In other words, k is some number (we just don't know what it is).

Now multiply EVERY data value by k to get:
Mona 40k
Sam 80k
Tony 80k
Alba 60k
Peter 110k

Now let's find the following:

Mean: Add up the values and divide by 5 (the number of people there) to get



So the mean of the data values of 40k, 80k, 80k, 60k, and 110k is 74k. What this means is that the mean is just the original mean multiplied by the constant k. So if k=2, then the new mean is 2*74=148

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Median: First write the values in ascending order:

40, 60, 80, 80, 110


Now multiply each value by k:

40k, 60k, 80k, 80k, 110k

From this list, the middle most value is 80k. Since the original median is 80, the new median is just the result of multiplying the original median of 80 by the constant k. I bet you can guess what's going to happen with the mode and the range.

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Mode:

Looking at the list


40k, 60k, 80k, 80k, 110k


we see that the mode is 80k since 80k repeats itself twice and it is the most frequent number. Because the original mode is 80, the new mode is just the product of the old mode and k.


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Range:

The range of the list


40k, 60k, 80k, 80k, 110k


is just the difference between the largest element (110k) and the smallest element (40k). In other words the range is: 110k - 40k = 70k which is exactly the product of the original range and the constant k.


So multiplying every element in a data set by a fixed number will just multiply the mean, median, mode, and range by that same fixed number. Try picking some specific numbers (like k=2, k=3, etc) to give you some examples.


Percentage-and-ratio-word-problems/252326: 1.if set A has 3 elements and set B has 4 elements:
a. what is the greatest number of elements that A n B can have? explain
the greatest number of elements that A n B can have is 3 b/c a is a subset of B and A and B
b. what the lest number of elements that A n B can have? explain
if a and B are disjoint than A and B has zero elements


2.solve the inequality and graph the solution set : (x- 4 is less than or equal to -6) or (2x > 8)
p.s i wrote less than or equal to b/c i couldnt find the symbol for it.


please and thank you
1 solutions

Answer 184182 by jim_thompson5910(28598) About Me  on 2009-12-26 17:24:50 (Show Source):
You can put this solution on YOUR website!
See this solution at the following link:

http://www.algebra.com/algebra/homework/Percentage-and-ratio-word-problems/Percentage-and-ratio-word-problems.faq.question.252266.html


Geometry_proofs/252317: i need help with the following proof. Ive put it into a link
can someone explain it please?
http://www2.edmastery.com/li/itemAssets/nnds_li%20-%20production%5Cdmeyer%5C16.bmp
1 solutions

Answer 184172 by jim_thompson5910(28598) About Me  on 2009-12-26 15:30:10 (Show Source):
You can put this solution on YOUR website!
When you have 3=-120x-84 and you want to solve for 'x', the next step would be to add 84 to both sides to get 3%2B84=-120x%2Bcross%28-84%29%2Bcross%2884%29 which then becomes 87=-120x. The property that you are using here is the addition property of equality. So the answer is C)


Quadratic_Equations/252256: 3x squared + 12x = -2
I can find the square sign on my computer so I just wrote out 3x squared
1 solutions

Answer 184089 by jim_thompson5910(28598) About Me  on 2009-12-25 17:41:03 (Show Source):
You can put this solution on YOUR website!

3x%5E2%2B12x=-2 Start with the given equation.


3x%5E2%2B12x%2B2=0 Add 2 to both sides.


Notice that the quadratic 3x%5E2%2B12x%2B2 is in the form of Ax%5E2%2BBx%2BC where A=3, B=12, and C=2


Let's use the quadratic formula to solve for "x":


x+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


x+=+%28-%2812%29+%2B-+sqrt%28+%2812%29%5E2-4%283%29%282%29+%29%29%2F%282%283%29%29 Plug in A=3, B=12, and C=2


x+=+%28-12+%2B-+sqrt%28+144-4%283%29%282%29+%29%29%2F%282%283%29%29 Square 12 to get 144.


x+=+%28-12+%2B-+sqrt%28+144-24+%29%29%2F%282%283%29%29 Multiply 4%283%29%282%29 to get 24


x+=+%28-12+%2B-+sqrt%28+120+%29%29%2F%282%283%29%29 Subtract 24 from 144 to get 120


x+=+%28-12+%2B-+sqrt%28+120+%29%29%2F%286%29 Multiply 2 and 3 to get 6.


x+=+%28-12+%2B-+2%2Asqrt%2830%29%29%2F%286%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%28-12%2B2%2Asqrt%2830%29%29%2F%286%29 or x+=+%28-12-2%2Asqrt%2830%29%29%2F%286%29 Break up the expression.


x+=+%28-6%2Bsqrt%2830%29%29%2F%283%29 or x+=+%28-6-sqrt%2830%29%29%2F%283%29 Reduce.


So the solutions are x+=+%28-6%2Bsqrt%2830%29%29%2F%283%29 or x+=+%28-6-sqrt%2830%29%29%2F%283%29


which approximate to x=-0.174 or x=-3.826


Matrices-and-determiminant/252267: Can cramer's rule be used for: if so what would I use for the middle equation for the coefficient of y and what would the constant be...???
x+y+z=2
2x=z
x-2y+2z=1
1 solutions

Answer 184086 by jim_thompson5910(28598) About Me  on 2009-12-25 17:35:33 (Show Source):
You can put this solution on YOUR website!
Since 2x=z can be rewritten as 2x%2B0y-z=0, this means that the middle coefficient for 'y' of the 2nd row is 0. Let me know if you need help with any more parts of the problem.


Systems-of-equations/252265: Hello
I have a problem that is nonlinear and cramer's rule or Gaussian elimination can't be used for. I'm trying to use substitution and factoring for this one but I'm coming up with the right thing... And I know its something that I'm missing I just can't see it.... it seems like the simplier the problem, I make mistakes.

Could you please assist me with solving this problem ..
Thanks
y=x^2-4x+7
y=x+1


1 solutions

Answer 184085 by jim_thompson5910(28598) About Me  on 2009-12-25 17:33:48 (Show Source):
You can put this solution on YOUR website!
y=x%5E2-4x%2B7 Start with the first equation.


x%2B1=x%5E2-4x%2B7 Plug in y=x%2B1


0=x%5E2-4x%2B7-x-1 Get everything to one side.


0=x%5E2-5x%2B6 Combine like terms.


0=%28x-3%29%28x-2%29 Factor the right side.


x-3=0 or x-2=0 Use the zero product property.


x=3 or x=2 Solve for 'x' in each equation.


Now for each 'x', plug them into y=x%2B1 to find the corresponding 'y' values.


So when x=3, then y=3%2B1=4 which gives the first ordered pair (3,4)


and when x=2, then y=2%2B1=3 which gives the second ordered pair (2,3)




Functions/252222: In A = xy - (1 - z/4)r^2, solve for r in terms of the other variables, r a positive number.
1 solutions

Answer 184047 by jim_thompson5910(28598) About Me  on 2009-12-25 00:59:26 (Show Source):
You can put this solution on YOUR website!
A+=+xy+-+%281+-+z%2F4%29r%5E2 Start with the given equation.


A+-+xy+=+-+%281+-+z%2F4%29r%5E2 Subtract xy from both sides.


%28A+-+xy%29%2F%28-%281+-+z%2F4%29%29+=+r%5E2 Divide both sides by -+%281+-+z%2F4%29.


-%28A+-+xy%29%2F%281+-+z%2F4%29+=+r%5E2 Reduce.


sqrt%28-%28A+-+xy%29%2F%281+-+z%2F4%29%29+=+r Take the square root of both sides. Note: Since 'r' is positive, we don't have to worry about the negative square root.


So the answer is r=sqrt%28-%28A+-+xy%29%2F%281+-+z%2F4%29%29


Note: if the original problem was A+=+xy+-+%28%281+-+z%29%2F4%29r%5E2, then the answer is r=sqrt%28-%28A+-+xy%29%2F%28%281+-+z%29%2F4%29%29 which simplifies to r=sqrt%28-%284%28A+-+xy%29%29%2F%281+-+z%29%29