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edjones answered: 7568 problems
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Equations/164733: Factor 10x^2-21x-10
1 solutions

Answer 121396 by edjones(7569) About Me  on 2008-10-29 18:49:58 (Show Source):
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10x^2-21x-10
10*-10=-100. What 2 factors of -100 have a sum of -21? Ans -25 and 4.
10x^2+4x-25x-10
=2x(5x+2)-5(5x+2)
=(2x-5)(5x+2)
.
Ed


Exponents/164730: evaluate is m=-2 and n=3: m^-2+n^-1

-2^-2+3^-1 = -8+(-3) = -11?

1 solutions

Answer 121393 by edjones(7569) About Me  on 2008-10-29 18:38:22 (Show Source):
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(-2)^(-2)+3^(-1)
=1/(-2)^2 + 1/3
=1/4 + 1/3
=3/12 + 4/12
=7/12
.
Ed


Equations/164719: rational equations: Solve for X using LCD method
x+1/3 + x-3/4 = 1/6
1 solutions

Answer 121390 by edjones(7569) About Me  on 2008-10-29 18:25:23 (Show Source):
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x + 1/3 + x - 3/4 = 1/6
12x+4+12x-9=2 LCD=12
24x-5=2
24x=7
x=7/24
.
Ed


Inequalities/164725: Write an inequality for the phrase.
eight less than a number x is at least 17
1 solutions

Answer 121388 by edjones(7569) About Me  on 2008-10-29 18:17:18 (Show Source):


Geometry_proofs/164726: what are parallel lines

1 solutions

Answer 121387 by edjones(7569) About Me  on 2008-10-29 18:14:16 (Show Source):
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straight railroad tracks.
They never meet.


Equations/164727: 20 = 6x+ 8
1 solutions

Answer 121386 by edjones(7569) About Me  on 2008-10-29 18:11:22 (Show Source):
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6x+ 8=20
6x+8-8=20-8
6x=12
6x/6=12/6
x=2
.
Ed


Miscellaneous_Word_Problems/164709: A batter in a baseball game drops a bunt down the first-base line. It rolls 42ft at an angle of 36 degrees with the base path. The pitcher's mound is 60.5ft from home plate: How far must the pitcher travel to pick up the ball? Answer to the nearest foot. Note a baseball field is a square.
I drew the field and the triangle within the square, but i dont think my picture is correct. i came up with 36.23 ft; that xoesnt seem correct to me. Please help
1 solutions

Answer 121385 by edjones(7569) About Me  on 2008-10-29 18:08:30 (Show Source):
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We have 2 sides of a triangle, 60.5 and 42. The angle between them is 45-36=9 deg. SAS triangle.
a^2=b^2+c^2-2bc*cosA
a^2=60.5^2+42^2-(2*60.5*42*cos(9)
=3660.25+1764-(5082*.987688)
=5424.25-5019.43
=404.818
a=sqrt(404.818)
=20.1201
Answer 20 ft.
.
Ed


test/164706: This question is from textbook
0.2y^2+0.03y=0.02
1 solutions

Answer 121383 by edjones(7569) About Me  on 2008-10-29 17:38:14 (Show Source):
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0.2y^2+0.03y=0.02
20y^2+3y=2 multiply each side by 100
20y^2+3y-2=0
20*-2=-40. What 2 factors of -40 add up to 3? Ans 8 & -5.
20y^2-5y+8y-2=0
5y(4y-1)+2(4y-1)=0 Factoring by grouping.
(5y+2)(4y-1)=0
5y=-2, 4y=1
y=-2/5, y=1/4
.
Ed


Travel_Word_Problems/164707: if a car goes one mile in one minute. how many miles an hour is this?
1 solutions

Answer 121380 by edjones(7569) About Me  on 2008-10-29 17:26:10 (Show Source):


Equations/164710: This question is from textbook
can someone help me with this two question.
Classify the function as a linear, quadratic, or exponential.
1. f(x) = -5x - 4
2. f(x) = (x - 5)(x + 4)
1 solutions

Answer 121378 by edjones(7569) About Me  on 2008-10-29 17:23:56 (Show Source):
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1. linear because a graph of f(x) is a straight line and it is of the 1st degree.
2. quadratic because it is a polynomial equation of the 2nd degree. Its graph is a parabola.
f(x)=x^2-x-20
.
Ed
.
graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C-5x-4%29
.
graph%28500%2C500%2C-10%2C10%2C-20%2C20%2Cx%5E2-x-20%29


Geometry_Word_Problems/164713: What is the perimeter of a rectangle 29 in wide, 22 in long?
1 solutions

Answer 121370 by edjones(7569) About Me  on 2008-10-29 17:08:17 (Show Source):
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29*2 + 22*2
=58+44
=102"
.
Ed


Miscellaneous_Word_Problems/163802: Three workers set out to plaster a ceiling. One can do the job alone in 2 hours, one in three hours and the last in 4 hours how long does it take them together to plaster the ceiling?
1 solutions

Answer 120668 by edjones(7569) About Me  on 2008-10-24 01:24:29 (Show Source):
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One can do 1/2 the job in 1 hr, another 1/3 and another 1/4 the job in 1 hr.
1/2 + 1/3 + 1/4
=6/12 + 4/12 + 3/12
=13/12 of the job in 1 hr together
12/13 of an hour to do the job working together.
.
Ed


Polynomials-and-rational-expressions/163774: 5x=y solve for x
1 solutions

Answer 120667 by edjones(7569) About Me  on 2008-10-24 01:18:07 (Show Source):
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5x=y
5x/5=y/5
x=y/5
.
Ed


Miscellaneous_Word_Problems/163803: one pipe fills a tank in 50 minutes another pipe in 75 how long does it take for both pipes together to fill a tanks?

1 solutions

Answer 120666 by edjones(7569) About Me  on 2008-10-24 01:03:13 (Show Source):
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One pipe does 1/50 of the job in 1 minute.
the other pipe doe 1/75 in 1 minute
1/50 + 1/75
=3/150 + 2/150 = 5/150 = 1/30 of the job in 1 minute.
So the tank will be filled in 30 minutes using both pipes.
.
Ed


Numbers_Word_Problems/163561: When 28 is added to 3 times a number y and the sum is divided by 2, the result is 2 times the number y. What is the value of y?
1 solutions

Answer 120531 by edjones(7569) About Me  on 2008-10-23 01:21:46 (Show Source):
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(3y+28)/2=2y
3y+28=4y
28=y
.
Ed


Permutations/163614: Determine the number of different three letter "words" that can be formed using the letters from the word "ARRANGE"
1 solutions

Answer 120530 by edjones(7569) About Me  on 2008-10-23 01:02:17 (Show Source):
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1st use each letter only once in the 3 letter word:
5P3=5!/(5-3)!=(5*4*3*2)/2=60
2nd use both double letters with one other letter. rrn rnr nrr There are 3 permutations for each of the 4 single letters=12 There are 2 sets of double letters so 24 are the possible permutations.
60+24=84 "words" altogether.
.
Ed


Graphs/163618: Describe what the graph of interval [-4,10] looks like
1 solutions

Answer 120529 by edjones(7569) About Me  on 2008-10-23 00:32:47 (Show Source):
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It is a dot located 4 lines left of the origin and 10 lines up.


Square-cubic-other-roots/163624: rationalize the denominator..plz
3+2sq-root of 5
divided by or over..
3sq-root 5-4
1 solutions

Answer 120526 by edjones(7569) About Me  on 2008-10-23 00:14:51 (Show Source):


Probability-and-statistics/163450: What's the probability that a sum of 7 or 11 appears at least twice, if the a pair of fair dice are tossed 3 times.
1 solutions

Answer 120416 by edjones(7569) About Me  on 2008-10-22 01:47:00 (Show Source):
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The probability of 11 on one roll is 2/36
The probability of 7 on one roll is 6/36
The probability of 7 or 11 on one roll is 8/36=2/9
(a+b)^3=a^3+3a^2b+3ab^2+b^3
Let a=2/9 and b=7/9
We are only interested in the 1st 2 terms:
(2/9)^3+3(2/9)^2(7/9)=.1262 answer.
.
Ed


Linear_Equations_And_Systems_Word_Problems/163453: Can you help me solve this problem: A repairman purchased some washing machine motors for a total of $224. When the unit cost decreased by $4, he was able to buy one extra motor for the same total price. How many motors did he buy originally?
1 solutions

Answer 120415 by edjones(7569) About Me  on 2008-10-22 01:11:13 (Show Source):
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Let n=number of motors & u=unit cost
A) n*u=224
B) (n+1)*(u-4)=224
.
A) u=224/n
B)
(n+1)*(224/n -4)=224
(n+1)((224-4n)/n)=224 LCD of 224/n -4
(n+1)(224-4n)=224n multiply each side by n to eliminate the fraction.
-4n^2+220n+224=224n
n^2-55n-56=-56n divide each side by -4
n^2+n-56=0
(n+8)(n-7)=0
n=7 motors at $32
8 motors at $28
.
Ed


Systems-of-equations/163226: This question is from textbook Prentice Hall Algebra 2 with Trigonometry
Nancy jogs and walks to school each day. She averages 4 km/h walking and 8 km/h jogging. The distance from home to school is 6km snd she makes the trip in 1 hour. How far does she jog in a trip?
1 solutions

Answer 120306 by edjones(7569) About Me  on 2008-10-21 03:34:56 (Show Source):
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st=d
Let j=time jogging and 1-j=time walking.
4(1-j)+8j=6
4-4j+8j=6
4+4j=6
4j=2
j=1/2 hr
8* 1/2=4 mi jogging.
.
Ed


Linear-equations/163243: Debbie is making apple dumplings. They have to be made from 6 inch square pieces of dough. In order to make 6 dumplings, what is the formula or equation to determine the size of the rectangle of dough?

1 solutions

Answer 120305 by edjones(7569) About Me  on 2008-10-21 03:06:04 (Show Source):
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6 inch square pieces are squares with each side 6". The area of each square is 6^2=36 in^2
A 36" by 6" rectangle of dough would allow the cutting out of six 6" square pieces of dough.
.
Ed


Functions/163249: x=1/2
f(x)=4x-2
1 solutions

Answer 120304 by edjones(7569) About Me  on 2008-10-21 02:58:00 (Show Source):
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x=1/2
f(x)=4x-2
f(x)=4(1/2) -2
f(x)=2-2
f(x)=0
.
Ed


Equations/163272: 4 - 8/3 q = 19
1 solutions

Answer 120303 by edjones(7569) About Me  on 2008-10-21 02:31:58 (Show Source):
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4-(8/3)q=19 I assume that this is the problem.
12-8q=57 multiply each side by 3.
-8q=45
q=-45/8
.
Ed


Inequalities/163274: Y + 1/2 = - 1/3 (x + 1/2)
I am not understanding solving for y using fractions.
1 solutions

Answer 120302 by edjones(7569) About Me  on 2008-10-21 02:23:47 (Show Source):
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y+ 1/2=-1/3(x+ 1/2)
y+ 1/2=-x/3 - 1/6
6y+3=-2x-1 multiply each side by 6 (LCM).
6y=-2x-4
y=-x/3-2/3
y=-(x+2)/3
.
Ed


Proportions/163190: write as an equation that represents the relationship between the given variables. Use k as the variation constant.
F varies jointly as h and inversely as the square of r
1 solutions

Answer 120301 by edjones(7569) About Me  on 2008-10-21 02:07:22 (Show Source):


test/163276: please help me evaluate 1)3x^0 2)(3x)^0.
are the results different? Why or why not are they different?
1 solutions

Answer 120300 by edjones(7569) About Me  on 2008-10-21 02:04:09 (Show Source):
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1)3 only x is to the 0 power.
2)1
.
Ed


Average/163277: the average of four numbers is 638.4 the first four numbers are 216 159.8 and 301.25 Find the fourth number.
1 solutions

Answer 120298 by edjones(7569) About Me  on 2008-10-21 02:01:27 (Show Source):
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216+159.8+301.25+x=638.4*4
677.05+x=2553.6
x=2553.6-677.05
x=1876.55
.
Ed


Inequalities/163052: can someone help me with this problem please
Solve the inequality.
x^2 - 1.01x - 83.19 < 0
(Give approximations rounded to the nearest hundredth.)
a. (-infinity, -8.63) U (9.64, infinity)
b. (9.64, -8.63)
c. (-infinity, -9.64) U (8.63, infinity)
d. (-9.64, 8.63)
1 solutions

Answer 120163 by edjones(7569) About Me  on 2008-10-20 02:48:54 (Show Source):
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x^2 - 1.01x - 83.19 < 0
Start with the equality x^2 - 1.01x - 83.19 = 0
x=-8.62982, x=9.63982 (quadratic formula)
These 2 numbers are inflection points.
We can select numbers below -8.7, between the 2 numbers and above 9.7 for x and see what sign y has.
x=-10 then x^2 - 1.01x - 83.19=26.91
x=0 then x^2 - 1.01x - 83.19=-83.91
x=10 then x^2 - 1.01x - 83.19=6.71
(-8.62, 9.64) Answer
.
Ed
.
graph%28500%2C500%2C-20%2C20%2C-100%2C100%2Cx%5E2-1.01x-83.19%29


Probability-and-statistics/163063: in one town, 80% of adults have health insurance. what is the probability that 7 adults selected at random from the town all have health insurance?
1 solutions

Answer 120162 by edjones(7569) About Me  on 2008-10-20 02:13:26 (Show Source):
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.8^7=.209715...


Probability-and-statistics/163064: assuming that boy and girl babies are equally likely, find the probability that a family with three children has all boys given that the first two are boys.
1 solutions

Answer 120160 by edjones(7569) About Me  on 2008-10-20 02:08:59 (Show Source):