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Length-and-distance/421929: Find the foci and vertices of the ellipse with equation x^2/9+y^2/16=1
1 solutions

Answer 294556 by ewatrrr(10682) About Me  on 2011-03-14 11:58:06 (Show Source):
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Hi
Standard Form of an Equation of an Ellipse is %28x-h%29%5E2%2Fa%5E2+%2B+%28y-k%29%5E2%2Fb%5E2+=+1+
where Pt(h,k) is the center with a and b determining the respective vertices distances from center.
x^2/9+y^2/16=1
Center(0,0) Vertices: (3,0),(-3,0) and (0,4),(0,4)
foci distance from center along major axis: sqrt%2816-9%29+=+sqrt%287%29
foci: (0,sqrt(7)),(0,-sqrt(7))



Exponents-negative-and-fractional/421895: I can't quite understand where I am going wrong.
-32a^-15b^10/-52a^13b^-14
I had answered it as 8b^4/13a^2
Wouldn't you change the places of the original exponents to make them positive and then subtract since you are dividing? The correct answer is 8b^24/13a^28. I cannot seem to grasp this idea of the negative exponents. I know you have to change the places to make them psoitive and that is what I had done. But it was marked wrong. This is the topic that is holding me back.
Thank You
1 solutions

Answer 294543 by ewatrrr(10682) About Me  on 2011-03-14 10:05:16 (Show Source):
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Hi
OK on your moving the 'a^-15' to the denominator to 'meet up' with the 'a^13'
You are then in a position to multiply them by adding their exponents.
-32%2Aa%5E%28-15%29%2Ab%5E%2810%29%2F-52a%5E%2813%29b%5E%28-14%29 |a%5E%28-15%29+=+1%2Fa%5E%2815%29
%288%2F13%29%28b%5E10+%2F%28a%5E%2813%29%2Aa%5E%2815%29b%5E%28-14%29%29%29
%288%2F13%29%28b%5E10+%2F%28a%5E%2813%2B15%29b%5E%28-14%29%29%29 |%28+x%5Em+%29%28+x%5En+%29+=+x%5E%28+m+%2B+n+%29

%288%2F13%29%28b%5E10+%2F%28a%5E%2828%29b%5E%28-14%29%29%29 |+1%2Fb%5E%28-14%29=+b%2814%29
%288%2F13%29%28%28b%5E10%2Ab%5E%2814%29%29+%2F%28a%5E%2828%29%29%29 |%28+x%5Em+%29%28+x%5En+%29+=+x%5E%28+m+%2B+n+%29
%288%2F13%29%28%28b%5E24%29+%2F%28a%5E%2828%29%29%29


Probability-and-statistics/421884: A survey of 1100 people in a certain city owns 860 microwave ovens 740 own DVD players and 590 own either a microwave oven AND a DVD player.
a. how many people in the survey own either a microwave oven or a DVD player
b. how many own neither a microwave oven nor a DVD player
c. How many own a microwave oven and do not own a DVD player
1 solutions

Answer 294537 by ewatrrr(10682) About Me  on 2011-03-14 09:24:02 (Show Source):
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Hi
1100 people
≥ 1 Both 1
Microwave 860
DVD Player 740
1600 -590 = 1010
a. how many own either a microwave oven or a DVD player: 1010
b. how many own neither a microwave oven nor a DVD player: 1100-1010 = 90
c. How many own a microwave oven and do not own a DVD player = 860-590= 270


Trigonometry-basics/421850: can you help me solve this fundamental identities....please..
1.) cosēθ(tanē θ+1)=1
2.) secē θcotē=1+cotē θ
3.)Sin θ__ =cscθ-cot θ
1+cos θ

1 solutions

Answer 294536 by ewatrrr(10682) About Me  on 2011-03-14 09:07:30 (Show Source):
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Hi
cosēθ(tanēθ+1)=1 | (tanēθ+1)= secθē = 1/cosēθ
cosēθ/cosēθ = 1
1 = 1
secēθ cotē=1+cotēθ
secēθcotē- cotēθ = 1
cotēθ(secēθ - 1) = 1 | secēθ - 1 = tanēθ
cotēθtanēθ = 1 | tanēθ = 1/cotēθ
cotēθ/cotēθ = 1
1 = 1
Sinθ/(1+cos θ) = cscθ-cot θ |cscθ = 1/sinθ and cotθ = cosθ/sinθ
Sinθ/(1+cos θ) = (1-cosθ)/sinθ
sinēθ = (1+cos θ)(1-cos θ)
sinēθ = 1 - cosēθ
sinēθ + cosēθ = 1 |pythagorean Identity


Probability-and-statistics/420941: The table shows the political affiliation for a random sample of American voters and their positions on the death penalty.
Favor Oppose
Democrat 270 130
Republican 115 220
Other 40 85
ok so i figure i add them all favor 425 & oppose 435

a. Determine the probability that a randomly selected person favors the death penalty.
is this correct thinking 435/425 ?????

b. Determine the probability that a randomly selected person is a democrat given that they favor the death penalty.
is this correct thinking 270/425 ???????
c. Determine the probability that a randomly selected person favors the death penalty given that they are a republican.
is this correct thinking 115/425 ?????


1 solutions

Answer 294007 by ewatrrr(10682) About Me  on 2011-03-11 12:44:09 (Show Source):
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Hi, nice preentation
Do like completing the table with Totals for more clarity:
Favor Oppose Total
Democrat 270 130 400
Republican 115 220 335
Other 40 85 125
total 425 435 860
a. P(a randomly selected person favors the death penalty) = 425/860
b. P(a randomly selected person is a democrat given that they favor the death penalty) 270/425
c.P(probability that a randomly selected person favors the death penalty given that they are a republican) 115/335


Average/420306: Factor the expression
20x^3y^2 + 28x^2y^4
1 solutions

Answer 293738 by ewatrrr(10682) About Me  on 2011-03-10 09:56:49 (Show Source):
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Hi
Factor the expression
20x^3y^2 + 28x^2y^4
4x^2y^2(5x + 7y^2)


Volume/420304: how much water can be stored in a tank that measures 5 inches long 5 inches wide and 6 inches high.
1 solutions

Answer 293737 by ewatrrr(10682) About Me  on 2011-03-10 09:55:04 (Show Source):
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Hi
Volume of tank = 5in * 5in * 6in = 150 in^3 of water (or about 2.6 quarts(US))


Linear_Equations_And_Systems_Word_Problems/420313: the perimetet of a rectangle is 50 meters. write a linear equation in 2 variables for this perimeter. use the equation to find x when y=20
1 solutions

Answer 293736 by ewatrrr(10682) About Me  on 2011-03-10 09:43:56 (Show Source):
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Hi

using x and y to represent the lengths of the respective sides.
2x + 2y = 50m
2x + 2*20 = 50m
2x = 10m
x = 5m


Sequences-and-series/420255: write the first five terms of the sequence
1.an=n+3
2.an=3nsquared2
3.an=nsquared2+n-6
4.an=16-nsquared2
5.an-2n over2+7
1 solutions

Answer 293733 by ewatrrr(10682) About Me  on 2011-03-10 09:12:54 (Show Source):
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Hi
write the first five terms of the sequence: substituting for n = 1 to 5
a%5Bn%5D+=+n+%2B3 {4,5,6,7,8...}
a%5Bn%5D+=+3n%5E2 {3,12,27,48,75...}
a%5Bn%5D+=+n%5E2%2Bn%2B6 {8,11,16,23,32...}
a%5Bn%5D+=+16-n%5E2 {15,12,7,0,-9,...}


Sequences-and-series/420258: Algebra:Arithmetic Sequence
"can you plz. help me on this problem
what is the indicated term in each of the arithmetic sequence
1.3,7,11,....8th term

1 solutions

Answer 293732 by ewatrrr(10682) About Me  on 2011-03-10 08:59:52 (Show Source):
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Hi,
taking the 1. as a typo:
arithmetic sequence: {1,3,7,11,...} d = 4
{{a[n]=a[1]+(n-1)*d}}}
{{a[8]= 1 +(7)*4 = 29}}}



Sequences-and-series/420010: I've been trying this problem for a while now. Please help me find the sum of the geometric sequence where:
a sub4=24 and a sub9= 768 and n=9.
thank you
1 solutions

Answer 293731 by ewatrrr(10682) About Me  on 2011-03-10 08:55:54 (Show Source):
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Hi
geometric sequence
a%5Bn%5D+=+a%5B1%5D%2Ar%5E%28n-1%29
a%5B4%5D+=+a%5B1%5D%2Ar%5E3+=+24 a%5B1%5D+=+24%2Fr%5E3
a%5B9%5D+=+a%5B1%5D%2Ar%5E8=+768
24/r^3 *r^8 = 768
r^5 = 32
r = 2 and a%5B1%5D+=+3


Sequences-and-series/420260: the 2nd and 6th terms are 1 and 27.find (a)the first term (b)common difference (c)10th term

1 solutions

Answer 293724 by ewatrrr(10682) About Me  on 2011-03-10 08:27:03 (Show Source):
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Hi
Arithmetic Series
a%5Bn%5D=a%5B1%5D%2B%28n-1%29%2Ad
a%5B2%5D=a%5B1%5D%2B%282-1%29%2Ad+=+1 | a%5B1%5D=+1+-+d
a%5B6%5D=a%5B1%5D%2B%286-1%29%2Ad+=+27
(1-d) + 5d = 27
4d = 26
d = 26/4 = 13/2 a%5B1%5D=+-11%2F2+
CHECKING our Answer***
a%5B2%5D=+-11%2F2+%2B+13%2F2+=+1


Probability-and-statistics/419831: Assist me with this difficult homework problem:
1. A survey of 51 pet owners revealed that 24 owned dogs, 28 owned cats, 11 owned turtles, 12 owned both dogs and cats, 7 owned both dogs and turtles, 3 owned both cats and turtles, and 2 owned all three. Find the number of pet owners who owned none of the three lovely animals.
The answer is not 26.
1 solutions

Answer 293718 by ewatrrr(10682) About Me  on 2011-03-10 07:49:27 (Show Source):
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Hi
survey of 51 pet owners: results described in the chart below:
Find the number of pet owners who owned none of the three lovely animals.
>= 1 D&C D&T C&T 1
Dog 24
Cat 28
Turle 11
ALL 2
65 -12 -7 -3 = 43
51 - 43 = 8 own none


Linear-systems/419775: The sum of two numbers is 25. Three times the smaller number is twice the larger number. Find the numbers.
1 solutions

Answer 293542 by ewatrrr(10682) About Me  on 2011-03-09 16:58:35 (Show Source):
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Hi
sum of two numbers is 25
Let x and (25-x) represent the smaller and larger respectively
Question states***
3x = 2(25-x)
Solving for x
5x = 50
x = 10, the smaller number. 15 the larger (25-10))
CHECKING our Answer***
30 = 2*15


Linear-systems/419776: The sum of two numbers is3. Four times the smaller, plus the larger, is -48. Find the numbers.
1 solutions

Answer 293541 by ewatrrr(10682) About Me  on 2011-03-09 16:56:14 (Show Source):
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Hi
sum of two numbers is 3
Let x and (3-x) represent the smaller and larger respectively
Question states***
4x + (3-x) = -48
Solving for x
3x = -51
x = -17, the smaller number. 20 the larger (3-(-17))
CHECKING our Answer***
-68 + 20 = -48


Linear-systems/419934: Solve the systems by graphing
3x-2y=-24
-3x-y=6
I put them in point slope for
I think:
y=3/2x + 12
y=-3x-6
Then created a T-chart
x y
0 12
2 15
x y
0 -6
1 -9
Can you please help me? I do not understand why I am stuck....
1 solutions

Answer 293540 by ewatrrr(10682) About Me  on 2011-03-09 16:51:56 (Show Source):
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Hi
3x-2y=-24 OR y= 3/2x + 12 (Green)
x=0, then y= 12
y=0 then x =-8
(0,12)and(-8,0)
-3x-y=6 OR y=-3x-6 (Blue)
x=0, then y=-6
y=0 then x= -2
(0,-6) and (-2,0)
Plotting points and connecting with Line
Lines Intersect at ordered pair Pt(-4,6)
This is the solution for this system



Graphs/419648: Find the y-intercept and the x-intercept for the slope: y= -x^2+2x-2
1 solutions

Answer 293539 by ewatrrr(10682) About Me  on 2011-03-09 16:34:15 (Show Source):
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Hi
y= -x^2+2x-2 |Note use of ^ for squared term
y-intercept (when x = 0) Pt(0,-2)
y= -(x-1)^2 -1 |completing the square Vertex Pt(1,-1)
x-intercept (when y = 0)
-(x-1)^2 -1 =0
(x-1)^2 = -1 NO real roots, Parabola does not cross the x-axis
x = 1 ą sqrt(-1)



Graphs/419649: Find the y-intercept and the x-intercept for the slope: y=-2x^2+4x+2
1 solutions

Answer 293537 by ewatrrr(10682) About Me  on 2011-03-09 16:28:27 (Show Source):
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Hi
y = -2x^2+4x+2 |Note use of ^ for squared term
y-intercept (when x = 0) Pt(0,2)
y= -2(x-1)^2 + 4 |completing the square Vertex Pt(1,4)
x-intercept (when y = 0)
-2(x-1)^2 + 4 =0
(x-1)^2 = 2
x = 1 ą sqrt(2) Pt(2.414,0) and Pt(-.414,0) the x-intercepts



Graphs/419906: I need help graphing 2x-3y=6 y=mx%2Bb and using the x- and y- intercepts. I've already got y=-2/3+2 (negative 2 over 3 plus 2). After that, I'm stuck. please and thank you.
1 solutions

Answer 293527 by ewatrrr(10682) About Me  on 2011-03-09 16:09:08 (Show Source):
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Hi
graphing
2x-3y=6 OR y =(2/3)x -2
|when x=0, then y= -2 When y =0 then x = 3 Pts (0,-2) & (3,0) on the line
Graph Points and connect with Line:

Might recommend substituting any possible values for ordered pairs (x,y)that may
be found...into 2x-3y = 6 to see if they would be correct ordered pairs


Probability-and-statistics/419669: A standard deck of cards is made up of 4 suits with 13 cards in each suit. If we randomly sample five cards from a standard poker deck, find the probability that all five cards selected are clubs.

1 solutions

Answer 293464 by ewatrrr(10682) About Me  on 2011-03-09 11:10:14 (Show Source):
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Hi
If we randomly sample five cards from a standard poker deck,
find the probability that all five cards selected are clubs.
without replacement:
P (five being all clubs) = 13%2F52%2A12%2F51%2A11%2F50%2A10%2F49%2A9%2F48= 154,440/311,875,200 = .000495
with replacement:
P (five being all clubs) = (1/4)^5


Probability-and-statistics/419763: a jar contains 7 green, 19 black and 13 pik marbles. A marble is drawn at random. What is the probability of it being a green or black?
1 solutions

Answer 293461 by ewatrrr(10682) About Me  on 2011-03-09 10:53:52 (Show Source):
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Hi
a jar contains 7 green, 19 black and 13 pink marbles.
39 marbles in ALL
ONE marble is drawn at random.
P(being a green 'or' black) = 7/39 + 19/39 = 26/39


Rational-functions/419385: Find the foci of the ellipse with the equation 18x^2+36y^2=648. Graph the ellipse.
1 solutions

Answer 293301 by ewatrrr(10682) About Me  on 2011-03-08 16:42:53 (Show Source):
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Hi
18x^2+36y^2=648
18x^2/648 + 36y^2/648 = 1
x^2/36 + y^2/18 = 1
sqrt(36-18) = sqrt(18) = 3sqrt(2)
foci are (3sqrt(2),0) and (-3sqrt(2),0)



Probability-and-statistics/419386: IF A STUDENT GUESSES THE ANSWER TO A MULTIPLE CHOICE QUESTION (consisting of 5 possibile answers of which only one is correct) then the odds against the student answering the queastion correctly is.........; and the odds in favor are.......?


my working:
4:1
1:4
1 solutions

Answer 293299 by ewatrrr(10682) About Me  on 2011-03-08 16:29:17 (Show Source):
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Hi
MULTIPLE CHOICE QUESTION (consisting of 5 possible answers of which only one is correct)
odds against guessing correctly 4:1
odds for guessing correctly 1:4 |good work
P(guessing correctly) = 1/5 = .20


Square-cubic-other-roots/419389: If the volume of a cube is 216 cubic inches, what is the length of each edge of the cube?
1 solutions

Answer 293297 by ewatrrr(10682) About Me  on 2011-03-08 16:25:11 (Show Source):
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Hi
Volume(cube) = s*s*s where s is the length of each edge
s^3 = 216 in^3
s = 6 in


Probability-and-statistics/419380: IF THE ODDS AGAINST AN EVENT 'A' IS GIVEN AS 4:7, WE CAN CONCLUDE THAT THE PROBABILITY OF EVENT 'A' OCCURING IS .............?

MY ANSWER: 7/11
1 solutions

Answer 293296 by ewatrrr(10682) About Me  on 2011-03-08 16:23:33 (Show Source):
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Hi
odds against 4:7
odds for 7:4
P(event ocurring) = 7/11 |good work


Quadratic-relations-and-conic-sections/419366: Write an equation of a parabola with a vertex at the origin and a directrix at y = 5
1 solutions

Answer 293295 by ewatrrr(10682) About Me  on 2011-03-08 16:19:24 (Show Source):
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Hi
parabola with a vertex at the origin and a directrix at y = 5
The standard form is %28x+-h%29%5E2+=+4p%28y+-k%29, where the focus is (h,k + p)
p = -5
parabola opening downward y = -20x^2



Probability-and-statistics/419353: ......= PASS FAIL TOTAL
MALE = 28 17 45
FEMALE= 21 19 40
TOTAL = 49 36 85

COMPUTE THE PROBABILTY OF RANDOMLY SELECTING A FEMALE OR A PERSON WHO PASSED?.....
1 solutions

Answer 293293 by ewatrrr(10682) About Me  on 2011-03-08 16:00:38 (Show Source):
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Hi, great presentation
......= PASS FAIL TOTAL
MALE = 28 17 45
FEMALE= 21 19 40
TOTAL = 49 36 85
P(selecting female 'or' a person who passed) = 40/85 + 49/85 - 21/85


Polynomials-and-rational-expressions/419342: how do u do 5n^2-7n+2=0
1 solutions

Answer 293276 by ewatrrr(10682) About Me  on 2011-03-08 15:27:59 (Show Source):
You can put this solution on YOUR website!

Hi
factoring
5n^2-7n+2=0 an^2 + bn + c
n+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
n+=+%287+%2B-+sqrt%289+%29%29%2F%2810%29+
n+=+%287+%2B-+sqrt%289+%29%29%2F%2810%29+
n+=+%287+%2B-+3%29%2F%2810%29+
n = 10/10 = 1 and n = 4/10 = 2/5
5(n-1)(n-2/5) = 0
Note:SUM of the inner product(-n) and the outer product(-2/5n) = -7/5n
5*-7/5n = -7n


Polynomials-and-rational-expressions/419337: can you help me with polynomial factoring? 2m^2-13m+15=0
1 solutions

Answer 293273 by ewatrrr(10682) About Me  on 2011-03-08 15:22:41 (Show Source):
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Hi
2m^2-13m+15=0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%2813+%2B-+sqrt%28+49+%29%29%2F%284%29+
x+=+%2813+%2B-+7%29%2F%284%29+
x = 20/4 and x = 6/4 = 3/2
2(m-5)(m-3/2) = 0
Note:SUM of the outside terms(-5m) and the inside terms(-1.5m) = -6.5m
2*-6.5m = -13m


Polynomials-and-rational-expressions/418997: factor each polynomial completely
36qģ+24qē+4q
1 solutions

Answer 293270 by ewatrrr(10682) About Me  on 2011-03-08 15:13:30 (Show Source):
You can put this solution on YOUR website!

Hi
factor each polynomial completely
36qģ+24qē+4q
4q(9q^2 + 6q + 1)
4q(3q + 1)(3q + 1)
Note:SUM of the inner product(3q) and the outer product(3q) = 6q


Polynomials-and-rational-expressions/419328: 2x^3 - 10 + 4x^2 - 5x
Factor by grouping
1 solutions

Answer 293268 by ewatrrr(10682) About Me  on 2011-03-08 15:05:45 (Show Source):
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Hi
Factoring by grouping
2x^3 - 10 + 4x^2 - 5x
2x^3 + 4x^2 - 5x - 10
2x^2(x+2) - 5(x+2)
(2x^2 -5)(x+2)