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Polynomials-and-rational-expressions/417384: Solve by factoring (w-13)^2=16
1 solutions

Answer 292205 by ewatrrr(10682) About Me  on 2011-03-04 08:04:50 (Show Source):
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Hi
Solve by factoring
%28w-13%29%5E2+=16 |Note use of ^ (uppercase 6 on Your keyboard)
w^2 - 26x + 169 = 16
w^2 -26x + 153
(w-9)(w-17) = 0
(w-9)= 0 w = 9
(w-17)= 0 w = 17
CHECKING our Answer***
w-13 = ± 4
w = 13 ± 4


test/417370: find the vertex, the line of symmetry, the maximum/minimum value of the quadric function and graph the function
f(x)3x^2-18+11
what is vertex
what is equation of the line of symmetry x=
what the maximum/minimum
1 solutions

Answer 292204 by ewatrrr(10682) About Me  on 2011-03-04 07:57:08 (Show Source):
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Hi
Using the vertex form of a parabola, y=a%28x-h%29%5E2+%2Bk where(h,k) is the vertex
f(x) = 3x^2-18x+11 |completing the square to put into vertex form
f(x) = 3(x^2-6)+11
f(x) = 3[(x-3)^2 - 9]+11
f(x) = 3(x-3)^2 - 16 Vertex is Pt(3,-16), minimum at this Pt ( a>)
Line of symmetry is x = 3



Exponential-and-logarithmic-functions/417397: Hi there :) If I wanted to cancel out a sqrt sighn with a small 3 in the upper left hand corner how would I do this? Thanks!
1 solutions

Answer 292203 by ewatrrr(10682) About Me  on 2011-03-04 07:49:10 (Show Source):
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Hi
Recommend re-posting with an example so as we as Tutors can best assist You.


Word_Problems_With_Coins/417295: Sue had 6 times as many quarters as Jim. Ben has twice as many quarters as Jim. Together they had $9. How much money did each person have?
1 solutions

Answer 292202 by ewatrrr(10682) About Me  on 2011-03-04 07:41:33 (Show Source):
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Hi
Let x, 6x, 2x represent Jim's, Sues's and Ben's quarters respectively
Question states***CENTS makes sense
25*9x = 900
Solving for x
x = 4, number of quarters Jim had. Sue 24 and Ben 8
CHECKING our Answer***
25*(4+24+8) = 25*36 = 900 or $9.00


Word_Problems_With_Coins/417331: A donation box contains 49 coins consisting of nickels, dimes, and quarters. The number of quarters is two more than twice the number of dimes. The total value of the coins is $3.30. Find the number of nickles, dimes, and quarters.
1 solutions

Answer 292201 by ewatrrr(10682) About Me  on 2011-03-04 07:35:43 (Show Source):
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Hi
49 coins. The number of quarters is two more than twice the number of dimes
Let x , (2x+2), [49 -(3x+2)] represent the number of dimes, quarters and nickels
Question states***CENTS makes sense
10x + 25(2x+2) + 5[49-(3x+2)] = 330
Solving for x
10x + 50x+ 50 + 245 -15x - 10 = 330
45x = 45
x = 1, the number of dimes, 4 Quarters and 44 Nickels
CHECKING our Answer***
10*1 + 25*4 + 5*44 = 110 + 220 = 330 or $3.30


Word_Problems_With_Coins/417391: If you have 60 coins that equal $4.45 in nickels and dimes. How many nickels and dimes do you have?
1 solutions

Answer 292200 by ewatrrr(10682) About Me  on 2011-03-04 07:23:37 (Show Source):
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Hi
60 coins
Let x and (60-x)represent the dimes and nickels respectively
Question states***CENTS makes sense
10x + 5(60-x) = 445
Solving for x
5x = 145
x = 29, number of dimes. 31 Nickels (60-29)
CHECKING our Answer***
10*29 + 5*31 = 290 + 155 = 445 or $4.45


Numbers_Word_Problems/417029: the sum of two numbers is 54.the larger number is 6 less than four times the smaller number.find the numbers
1 solutions

Answer 292199 by ewatrrr(10682) About Me  on 2011-03-04 07:12:52 (Show Source):
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Hi
the larger number is 6 less than four times the smaller number
Let x and ( 4x-6) represent the smaller and larger number respectively
Question states***
x + (4x-6) = 54
Solving for x
5x = 60
x = 12 The two numbers are 12 and 42 (48-6)
CHECKING our Answer***
12 + 42 = 54


Numbers_Word_Problems/417292: Twice a number is the same as 10 less 3 times the number.
1 solutions

Answer 292198 by ewatrrr(10682) About Me  on 2011-03-04 07:10:09 (Show Source):
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Hi
Let x represent the number
Question states***
2x = 3x-10
Solving for x
10 = x
CHECKING our Answer***
20 = 30 - 10


Numbers_Word_Problems/417383: divide 224 into two parts such that when the larger part is divided by the smaller part, the quotient is 2 and the remainder is half of the smaller part. find the larger part.
1 solutions

Answer 292197 by ewatrrr(10682) About Me  on 2011-03-04 07:08:36 (Show Source):
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Hi
divide 224 into two parts
Let x and (224-x) represent the smaller and larger part respectively
Question states***
%28224-x%29%2Fx+=+2+%2B+%281%2F2%29x
Solving for x
2(224-x) = 4x + x^2 |Multiplying thru by 2x
x^2 +6x -448 = 0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-6+%2B-+sqrt%28+1828%29%29%2F%282%29+
x+=+-3+%2B-+sqrt%28+457%29
x = 18.3776 | Tossing out negative solution
CHECKING our Answer***
205.6224/18.3776 = 11.1888 = 2 + (1/2)18.3776 = 2 + 9.1888


Human-and-algebraic-language/416940: Two angles are complementry if the sum of their measures is 90*. The measure of the first angle is 6* less than 4 times the second angle. Find the measure of the first angle. Round to tenth of degree.
1 solutions

Answer 292049 by ewatrrr(10682) About Me  on 2011-03-03 16:46:20 (Show Source):
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Hi
The measure of the first angle is 6* less than 4 times the second angle
Let x and (4x-6° )represent the second and first angle
x + (4x-6°) = 90°
5x = 96°
x = 19.2° The first angle is 70.8° (4*19.2° - 6°)


Numbers_Word_Problems/416990: How do i work out a problem where you have two consecutive even integers, such that five times the first integer is equal to four times the second integer?
1 solutions

Answer 292046 by ewatrrr(10682) About Me  on 2011-03-03 16:40:56 (Show Source):
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Hi
two consecutive even integers
Let x and (x+2)represent the smaller and larger respectively
Question states***
5x = 4(x+2)
Solving for x
x = 8 The two consecutive even integers are 8,10
CHECKING our Answer***
5*8 = 4*10 = 40


Quadratic_Equations/416994: How do you solve x2=36
1 solutions

Answer 292043 by ewatrrr(10682) About Me  on 2011-03-03 16:38:23 (Show Source):


Quadratic_Equations/417000: Shelly is 5 years older than Michele. Four years ago the sum of their ages was 65. Find the age of each person now.
Shelly is ? years
Michele is ? years
1 solutions

Answer 292042 by ewatrrr(10682) About Me  on 2011-03-03 16:37:10 (Show Source):
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Hi
Shelly is 5 years older than Michele
Let x and (x+5) represent Michele's and Shelly's ages NOW respectively
Question states*** 4 yrs ago...
(x-4) + [(x-4) +5] = 65
Solving for x
2x = 68
x = 34, Michele's age now. Shelly is 39
CHECKING our Answer***
35 + 30 = 65


Linear-systems/416996: I am having alot of trouble with this problem. plz help
3y+x=-1
x=-3y
1 solutions

Answer 292038 by ewatrrr(10682) About Me  on 2011-03-03 16:31:47 (Show Source):
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Hi
solving by substitution
x = -3y
3y + x = -1
3y + (-3y) = -1
0 ≠ -1 there is NO solution


Average/416997: A Student has two test scores. The difference between the scores is 12 and the mean, or average of the scores is 80. what are the two scores?
1 solutions

Answer 292037 by ewatrrr(10682) About Me  on 2011-03-03 16:29:31 (Show Source):
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Hi
difference between the scores is 12
Let x and (x-12) represent the two scores
Question states***
[x + (x-12]/2 = 80
Solving for x
[x + (x-12] = 160
2x = 172
x = 86 the two scores 74 and 86
CHECKING our Answer***
(74 + 86)/2 = 160/2 = 80




Problems-with-consecutive-odd-even-integers/416928: Find the area of a trapezoid with a height of 4 m and bases of 13 m and 22 m.can some one show me how to do this
1 solutions

Answer 292021 by ewatrrr(10682) About Me  on 2011-03-03 15:35:40 (Show Source):
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Hi
Find the area of a trapezoid with a height of 4 m and bases of 13 m and 22 m.
Area (trapezoid) = %28b%5B1%5D+%2B+b%5B2%5D%29%2F2%29h
A = (35m/2)*4 = 70 m^2


Probability-and-statistics/416946: A pet supplier has a stock of parakeets of which 30% are blue parakeets. A pet store orders 3 parakeets from this supplier. If the supplier selects the parakeets at random, what is the chance that the pet store gets exactly one blue parakeet?
1 solutions

Answer 292013 by ewatrrr(10682) About Me  on 2011-03-03 14:49:40 (Show Source):
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Hi
Note: The probability of x successes in n trials is:
P = nCx* p%5Ex%2Aq%5E%28n-x%29 where p and q are the probabilities of success and failure respectively.
In this case p =.3 and q = .7
nCx = n%21%2F%28x%21%28n-x%29%21%29
P(that the pet store gets exactly one blue parakeet) = 1-P(none) = 1 - (.7)^3


Parallelograms/416957: is having One pair of consecutive angles are congruent enough information to prove a quadrilateral is a parallelogram
1 solutions

Answer 292011 by ewatrrr(10682) About Me  on 2011-03-03 14:45:59 (Show Source):
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Hi
is having One pair of consecutive angles are congruent
enough information to prove a quadrilateral is a parallelogram?
NO, one of the following conditions must be shown to be true.
1) If a quadrilateral has one pair of sides that are both parallel and congruent,
then the quadrilateral is a parallelogram.
2) If the opposite sides of a quadrilateral are congruent,
then then quadrilateral is a parallelogram.
3) Opposites sides are parallel.
4) 'Opposite angles are congruent'
5) Diagonals bisect each other.


Linear-equations/416944: Use this table to answer the following questions:
x y
1 -1/4
2 -1/2
3 -3/4
4 ???

Between x and y, would the correlation be positive or negative?

What is the missing value of y in the table?
How would the values of this table be interpreted in terms of linear regression?

If a "line of best fit" is placed among these points plotted on a coordinate system, would the slope of this line be positive or negative?

1 solutions

Answer 292010 by ewatrrr(10682) About Me  on 2011-03-03 14:38:55 (Show Source):
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Hi
y = (-1/4)x negative correlation
y = (-1/4)*4 = -1
y = (-1/4)x is a function representative of a line
Slope of this line is = (-1/4) and is < 0 or negative


Probability-and-statistics/416622: Hi I got a problem of solving this problem: Please help me I badly need it.
7. A random sample of 12 preschool pupils were rated by their teacher on their reading readiness based on a scale of 25 points at the start of the school year. The same pupils were rated by the same teacher at the end of the school year. The ratings are shown in the table below
Pupil 1 2 3 4 5 6 7 8 9 10 11 12
Start 25 22 20 21 20 15 17 22 19 16 19 18
End 25 23 23 22 22 20 19 20 18 18 21 23

Is there significant difference in the reading readiness of the pupils at the start and at the end of the
school year? Test at 0.05 level of significance.

1 solutions

Answer 292007 by ewatrrr(10682) About Me  on 2011-03-03 14:30:38 (Show Source):
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Hi
Start 25 22 20 21 20 15 17 22 19 16 19 18
Mean[S]= 18.5833
SD[S] = 3.8720
End 25 23 23 22 22 20 19 20 18 18 21 23
mean[E] = 21.1667
SD[E} = 2.2088
t =
t = -2.0075
P(t<-2.0075) = .02 (one-tailed) .04 (two-tailed)
At the .05 level ofsignificance: .04 <.05
there is reason to believe there is a dfference in the reading readiness of the
pupils at the start and at the end of the school year, however at a lower
confidence interval there would not.


Probability-and-statistics/416931: how do you work out probibility????
1 solutions

Answer 292005 by ewatrrr(10682) About Me  on 2011-03-03 14:21:25 (Show Source):
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Hi
Recommend posting a particular example so as we as Tutors
can best be of assistance to You.


Percentage-and-ratio-word-problems/416942: On Patrick's history test he answered 6 true/false uestions and 14 multiple choice uestions correctly, he missed 1 multiple choice and 4 true-false. Of the uestions Patrick answered correctly, what percent were true-false questions?
1 solutions

Answer 292003 by ewatrrr(10682) About Me  on 2011-03-03 14:18:58 (Show Source):
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Hi
true/false multiple choice total
correctly 6 14 20
incorrectly 4 1 5
total 10 15 25
Of questons answered correctly (20)what % were T/F questions
6/20 = .30 or 30%


Probability-and-statistics/416671: a card is chosen at random from a pack of 52 playing cards.find the probability that the card is king or a red card
1 solutions

Answer 291984 by ewatrrr(10682) About Me  on 2011-03-03 11:46:00 (Show Source):
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Hi
a card is chosen at random from a pack of 52 playing cards.
P( king 'or' a red card)= P(king) + P(red) - P(both) = 4/52 + 26/52 - 2/52


Probability-and-statistics/416722: What is the probability that three tails come up on a throw of three dimes?
1 solutions

Answer 291983 by ewatrrr(10682) About Me  on 2011-03-03 11:43:11 (Show Source):
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Hi
What is the probability that three tails come up on a throw of three dimes?
P(tails) = 1/2
P(3 tails on 3 throws) = (1/2)^3 = 1/8


Probability-and-statistics/416737: In the tests of a new pharmaceutical product, data were
collected for use in the approval process required by the
U.S. Food and Drug Administration (FDA). Some participants
were given a placebo, an inert substance that
looks like the drug; others were given the drug. The
data are shown in the following table:
Drug: No Help 22 Help 47
Placebo: No Help 31 Help 20
What is the probability that:
a) the participants perceived that their “medication”
helped if they received the drug?
b) the participants perceived that their “medication”
helped if they received the placebo?
c) the participants perceived that their “medication”
helped?
I'm having a huge issue with this. Could you please show your work, or just explain how it's done so I can learn the method as well as understand what the answers are? Thanks so much!!!!
1 solutions

Answer 291982 by ewatrrr(10682) About Me  on 2011-03-03 11:38:42 (Show Source):
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Hi
No Help Help Total
Drug: 22 47 69
Placebo: 31 20 51
Total 53 67 120
What is the probability that:
a) the participants perceived that their “medication”
helped if they received the drug? 47/69
b) the participants perceived that their “medication”
helped if they received the placebo? 20/51
c) the participants perceived that their “medication”
helped? 67/120


Probability-and-statistics/416795: Assume the probability that an employee selling products is successful in a randomly selected sales call is 0.5.
Assume sales calls are independent and the employee is doing 2 sales calls.
What is the probability that at least one of the two sales calls is successful?
1 solutions

Answer 291977 by ewatrrr(10682) About Me  on 2011-03-03 11:30:34 (Show Source):
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Hi
Note: The probability of x successes in n trials is:
P = nCx* p%5Ex%2Aq%5E%28n-x%29 where p and q are the probabilities of success and failure respectively.
In this case p = .5 and q = .5
nCx = n%21%2F%28x%21%28n-x%29%21%29
Assume sales calls are independent and the employee is doing 2 sales calls
P(at least one of the two sales calls is successful) = 1-P(none)= 1 - (.5)^2
P(at least one of the two sales calls is successful) = .75


Probability-and-statistics/416884: What is your probability of not getting a spade from a deck of 52 cards?
1 solutions

Answer 291974 by ewatrrr(10682) About Me  on 2011-03-03 11:25:52 (Show Source):
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Hi
Total of 52 cards of which 13 are spades
P(no spade) = 1 - P(spade) = 1 - 13/52 = 39/52 = 3/4


Probability-and-statistics/416724: What is the probability of getting a 2 or a 12 on two dice?
1 solutions

Answer 291972 by ewatrrr(10682) About Me  on 2011-03-03 11:23:32 (Show Source):
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Hi
P(getting a 2 'or' 12 on two dice ) = 1/36 + 1/36 = 2/36 = 1/18
___1_2_3__4__5__6
1|_2_3_4__5__6__7
2|_3_4_5__6__7__8
3|_4_5_6__7__8__9
4|_5_6_7__8__9_10
5|_6_7_8__9_10_11
6|_7_8_9_10_11_12


Probability-and-statistics/416725: What is the probability of getting a 9 on two dice?
1 solutions

Answer 291970 by ewatrrr(10682) About Me  on 2011-03-03 11:21:43 (Show Source):
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Hi
P(getting a 9) = 4/36 = 1/9
___1_2_3__4__5__6
1|_2_3_4__5__6__7
2|_3_4_5__6__7__8
3|_4_5_6__7__8__9
4|_5_6_7__8__9_10
5|_6_7_8__9_10_11
6|_7_8_9_10_11_12


Probability-and-statistics/416881: What is the probability of not getting a 9 on two dice?
1 solutions

Answer 291968 by ewatrrr(10682) About Me  on 2011-03-03 11:20:35 (Show Source):
You can put this solution on YOUR website!

Hi
P(not getting a 9) = 1 - P(9) = 1 - 4/36 = 32/36 = 8/9
___1_2_3__4__5__6
1|_2_3_4__5__6__7
2|_3_4_5__6__7__8
3|_4_5_6__7__8__9
4|_5_6_7__8__9_10
5|_6_7_8__9_10_11
6|_7_8_9_10_11_12


Rectangles/416861: Picture of a rectangle that represents a floor that is 20 x 15. Another rectangle inside that one representing an area rug. The rug and the floor are similar rectangles with perimeters in the ratio of 5 to 3. What is the area of the rug?
I'm thinking I'm doing proportions but not sure how to do it.
Thanks
1 solutions

Answer 291957 by ewatrrr(10682) About Me  on 2011-03-03 10:32:22 (Show Source):
You can put this solution on YOUR website!

Hi
perimeters in the ratio of 5 to 3
floor that is 20 x 15: P =70
Let x represent the P of the rug
5%2F3+=+70%2Fx |Cross Multiplying to solve for x
5x = 210
x = 42, the perimeter of the rug. (OR 21 the sum of its length and width)
The rug and the floor are similar rectangles
20%2F15+=+%2821-x%29%2Fx |Cross Multiplying to solve for x
20x = 15*(21-x)
35x = 15*21
x = 15*21/35
x = 9 the rug is 12 x 9. It's area is 108
CHECKING our Answer***
20/15 = 12/9 = 4/3