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Miscellaneous_Word_Problems/241178: I have literally spent an entire day on this question. I think that it must be an inequality and some division must take place, but I am unable to find the solution. Here is the question:
A car rental company has two rental rates. Rate 1 is $63 per day plus .18 per mile. Rate 2 is $126 per day and .09 per mile. If you plan to rent a car for one week, how many miles would you need to drive to pay less by taking rate 2?
Any help is greatly appreciated.
1 solutions

Answer 176616 by scott8148(3382) About Me  on 2009-11-20 16:38:12 (Show Source):
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7 days in a week
set the two costs equal to find the "break even" milage

7(63) + .18m = 7(126) + .09m

subtracting [.09m + 7(63)] ___ .09m = 7(63)

dividing by .09 ___ m = 7(700) = 4900 miles

you need to drive MORE THAN this to save money with rate 2


Miscellaneous_Word_Problems/240608: Radioactive element R decays exponentially at a rate of 4% per year. If we begin with 5 grams of R, how long (to the nearest tenth of a year) will it take for only 3 grams to remain?
I started with the A=Aoe^rt where A=3 Ao=5 r=0.04 and t is what I needed to find. I then to ln3=ln5+0.04tlne. Then I got the 0.04t=(ln3-ln5)/lne....
1 solutions

Answer 176269 by scott8148(3382) About Me  on 2009-11-18 22:52:04 (Show Source):
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3 = 5 e^(-.04t)

.6 = e^(-.04t)

ln(.6) / -.04 = t



Polynomials-and-rational-expressions/240560: Factor this equation:
2pq-4p^2+2pr
I am trying to help my son and am totally lost.
1 solutions

Answer 176241 by scott8148(3382) About Me  on 2009-11-18 20:33:37 (Show Source):
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parents stick together...

each term contains 2p
___ factoring this gives ___ 2p (q - 2p + r)


Geometry_Word_Problems/240524: The height of a cylinder is twice the diameter. Express the total surface area A as a function of the height h.
This question really stump me can you show the work as well for me?
1 solutions

Answer 176238 by scott8148(3382) About Me  on 2009-11-18 20:29:32 (Show Source):
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"The height of a cylinder is twice the diameter" ___ h = 2d ___ h/2 = d ___ h/4 = r

A = LA + ends = [2 * pi * r * h] + [2 * pi * r^2] = [2 * pi * h/4 * h] + [2 * pi * (h/4)^2]

A = [2 * pi * (h^2 / 4)] (5 / 4) = 5/8 (pi * h^2)


Polynomials-and-rational-expressions/240538: Please help me out with this equation:

7/8 - 2/11 = x/44

I multiplied the two sides by the LCD, and ended up with a fraction that could not be reduced, but the question was asking for an answer in reduced form.
Please help me! It would be greatly appreciated!
1 solutions

Answer 176231 by scott8148(3382) About Me  on 2009-11-18 20:08:29 (Show Source):
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77/88 - 16/88 = (2x)/88

77 - 16 = 2x

61 = 2x

61/2 = x ___ this is as reduced as it gets


Functions/240536: For the quadratic function find the vertex, and x-intercept, y-intercept.
g(x)=x^2-6x+13
I have the vertex (3,4), but I'm having trouble finding the x and y intercepts.
(x-3)^2+4 (this is what i used to find the vertex)
1 solutions

Answer 176229 by scott8148(3382) About Me  on 2009-11-18 20:03:03 (Show Source):
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the x-intercept(s) (when y=0) are the roots ___ find with the quadratic formula

the y-intercept (when x=0) is just the c term (ax^2 + bx + c)


Signed-numbers/240530: -8(x-3) +12x= 15-(2x +3)


answer: -2 (anyone can show me why the answer is -2 and can give a full break down thank you).
1 solutions

Answer 176226 by scott8148(3382) About Me  on 2009-11-18 19:56:31 (Show Source):
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distributing ___ -8x + 24 + 12x = 15 - 2x - 3

collecting terms ___ 4x + 24 = -2x + 12

adding 2x and subtracting 24 ___ 6x = -12

dividing by 6 ___ x = -2


Linear-equations/240508: Okay, my homework says you have to create a table, and graph the coordinates for this equation... x+y=1
I know how to se up the table, but I don't know how to solve the equation because of the y number!!

1 solutions

Answer 176224 by scott8148(3382) About Me  on 2009-11-18 19:51:15 (Show Source):
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the table is of x and y pairs that make the equation true
you pick a value for x, and then find the y value

if x is 0, then y must be 1

if x is -4, then y must be 5

and so on...


Quadratic-relations-and-conic-sections/240467: I'm in dire need of help on my Honors pre-calculus assignment.
I'm given the foci (3,+-2) and the x intercepts of -1 and 7 .
How do I find the equation of the conic (parabola, hyperbola, or ellipse) described?
1 solutions

Answer 176221 by scott8148(3382) About Me  on 2009-11-18 19:43:17 (Show Source):
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there are two foci, in a VERTICAL line, symmetric about the x-axis

if this were a hyperbola, there would be NO x-intercepts

so you have an ellipse
___ centered at (3,0)
___ the length of the minor axis is ___ 2b = 7 - -1 = 8 ___ so, b = 4
___ distance from center to focus (c) is 2
___ a^2 = b^2 + c^2 = 16 + 4 = 20

[(x - 3)^2 / 16] + [(y - 0)^2 / 20] = 1


Coordinate-system/240489: I am asked to find the slope of two lines, each in the same quadrant, quadrant 1. There are no coordinates. Is there a formula I should be using?
1 solutions

Answer 176193 by scott8148(3382) About Me  on 2009-11-18 18:22:42 (Show Source):
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the lines should have equations

solve the equations for y
___ solutions of the form, y = mx + b

the x-coefficient (m), is the slope of the line

the constant term (b), is the y-intercept (where the line crosses the y axis)


Linear_Equations_And_Systems_Word_Problems/240474: Please help me write out and solve this equation:
A store owener sells two pairs of running shoes for each pair of high tops. He plans to order 144 pairs of shoes. How many pairs should be high tops?
1 solutions

Answer 176187 by scott8148(3382) About Me  on 2009-11-18 18:17:12 (Show Source):
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"A store owener sells two pairs of running shoes for each pair of high tops" ___ r = 2h

"He plans to order 144 pairs of shoes" ___ r + h = 144

two unknowns (r and h) and two equations

substituting ___ (2h) + h = 144 ___ h = 48

substituting ___ r = 2(48) = 96


Linear_Equations_And_Systems_Word_Problems/240475: Please help me write out and solve this equation:
At the Shake Shack two orders of fries and four shakes costs $5.90. How much is an order of fries.
1 solutions

Answer 176180 by scott8148(3382) About Me  on 2009-11-18 18:11:00 (Show Source):
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2f + 4s = $5.90

not enough information to solve
___ in general, you need as many independent equations as there are unknowns


Square-cubic-other-roots/240479: I'm really stuck on this problem, I don't think the answer is 800 or 28.28. Any help is appreciated. Please show work if you can so I can beat this in my head. Thanks to all that help!
√500 + √300
1 solutions

Answer 176175 by scott8148(3382) About Me  on 2009-11-18 18:07:57 (Show Source):
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extract (factor out) any WHOLE roots

√100 √5 + √100 √3

10 √5 + 10 √3


Equations/240364: Please help me understand the steps for solving this problem. The value of a two-digit number is twice as large as the sum of its digits. If the digits were reversed, the resulting number would be 9 less than 5 times the original number. Find the original number.
1 solutions

Answer 176124 by scott8148(3382) About Me  on 2009-11-18 15:29:54 (Show Source):
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let t="tens digit" and u="units digit"

"The value of a two-digit number is twice as large as the sum of its digits" ___ 10t + u = 2(t + u)
___ 10t + u = 2t + 2u
___ 8t = u ___ (there is only one pair of digits that works here)

"If the digits were reversed, the resulting number would be 9 less than 5 times the original number"
___ 10u + t = 5(10t + u) - 9
___ 10u + t = 50t + 5u - 9
___ 5u + 9 = 49t

substitute the value of u from the 1st part to find the value of t
___ then substitute t back to the 1st part to find the value of u


Travel_Word_Problems/239947: At 8:00 am the smiths left a campground driving at 48 mi/hour. At 8:20 the Garcias left the same campground and followed the same route driving at 60 mi/hour. At what time did they overtake the Smiths?
I thought that I had to take 20/60 to get 1/3, to make minutes into hours, and add it to 60t. Then have 48t equal that. (Shown Below)
48t = 60(t+1/3)
Then, I distributed, and got:
48t = 60t + 20
I subtracted 60t from 48t, and got this:
-28t = 20
I divided 28 by 20, and got 1.4, but I'm not sure if my answer is right. Can you help me?

1 solutions

Answer 175959 by scott8148(3382) About Me  on 2009-11-17 16:19:20 (Show Source):
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you've got the times and speeds reversed

they overtake when they have travelled the same DISTANCE (rate x time)

the shorter time goes with the faster speed

60 t = 48 (t + 1/3) ___ the Smiths had a 20 min head start

12 t = 16 ___ t = 4/3 or 1:20

8:20 + 1:20 = 9:40


Equations/239235: please help me solve this:
6s^2+29s-42
1 solutions

Answer 175692 by scott8148(3382) About Me  on 2009-11-15 21:18:53 (Show Source):
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(6s - 7) (s + 6)


Numbers_Word_Problems/238959: How many positive integers x are there such that 3x has three digits and 4x has four digits?
1 solutions

Answer 175623 by scott8148(3382) About Me  on 2009-11-15 16:22:57 (Show Source):
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99 > 3x > 1000

33 > x > 333 1/3 ___ 34 to 333


999 > 4x > 10000

249 3/4 > x > 2500 ___ 250 to 2500


250 to 333 ___ 84 integers


absolute-value/239010: |5x+2|>2
1 solutions

Answer 175619 by scott8148(3382) About Me  on 2009-11-15 16:11:31 (Show Source):
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5x + 2 > 2 ___ and ___ 5x + 2 < -2

5x > 0 ___ x > 0

5x < -4 ___ x < -4/5

x > 0 ___ and ___ x < -4/5


Finance/239008: The Future Teacheers of America Club at Paint Branch High School is making a healthy trail mix to sell to students during lunch. The mix will have three times the number of pounds of raisins as sunflower seeds. Sunflower seeds cost $4.00 and raisins cost $1.50 per pound. If the group has $34.00 on the raisins and sunflower seeds, how many pounds of each should they buy?
1 solutions

Answer 175616 by scott8148(3382) About Me  on 2009-11-15 16:05:10 (Show Source):
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let x=sunflower, so 3x=raisins

(4)(x) + (1.5)(3x) = 34


Quadratic_Equations/239007: Venture Capital:
Henry invested $12000 in a new resturant. When the resturant was sold two years later, he received $27000. Find the average annual return by solving the equation 12,000(1+r)^2=27000.
used the foil to solve the (1+r)^2 or (1+r)(1+r)
12000(1+2r+r^2)=27000
12000+24,000r+12000r^2=27000
-15000+24,000r+1200r^2=0
THis is as far as I could get. Not sure my next step.
1 solutions

Answer 175615 by scott8148(3382) About Me  on 2009-11-15 16:00:39 (Show Source):
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dividing by 12000 ___ (1 + r)^2 = 9 / 4

taking sqrt ___ 1 + r = 3 / 2

subtracting 1 ___ r = 1 / 2 ___ or .5 ___ or 50%

pretty good investment...


Quadratic_Equations/239003: Winter Wheat question: WHile finding the amount of seed needed to plant his three square wheat fields, Hank observed that the side of one field was 1 Kilometer longer than the side of the smallest field and that the side of the largest field was 3 kilometer longer than the side of the smallest field. If the total area of the three fields is 38 square kilometers, then what is the area of each field?
x^2+(x+1)^2=(x+3)^2=38
Used the foil method to solve (x+1)(x+1) and (x+3)(x+3)
x^2+x^2+2x+1+x^2+6x+9=38
3x^2+8x+10=38
3x^2+8x-28=0
I know this is wrong because I can't solve.
Any suggestions?

1 solutions

Answer 175614 by scott8148(3382) About Me  on 2009-11-15 15:53:04 (Show Source):
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(3x + 14) (x - 2) = 0


Polynomials-and-rational-expressions/238954: Solve.
(t-5)^2=2(5-t)
1 solutions

Answer 175611 by scott8148(3382) About Me  on 2009-11-15 15:41:30 (Show Source):
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(t-5)^2 + 2(t-5) = 0

(t-5) [(t-5) + 2] = 0

(t-5) (t-3) = 0

t-5 = 0 ___ t = 5

t-3 = 0 ___ t = 3


Polynomials-and-rational-expressions/238952: Factor completely.
y^2(y+1)-4y(y+1)-21(y+1)
1 solutions

Answer 175607 by scott8148(3382) About Me  on 2009-11-15 15:34:48 (Show Source):
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(y + 1) (y - 7) (y + 3)


Polynomials-and-rational-expressions/238951: Factor completely, if possible.
(y-5)^2 -36q^2
1 solutions

Answer 175606 by scott8148(3382) About Me  on 2009-11-15 15:33:06 (Show Source):
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difference of squares

[(y - 5) + 6q] [(y - 5) - 6q]


Polynomials-and-rational-expressions/238950: Factor.
(a+4)^2 - 2(a+4)+1
1 solutions

Answer 175604 by scott8148(3382) About Me  on 2009-11-15 15:29:52 (Show Source):
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[(a + 4) - 1]^2 or (a + 3)^2


Trigonometry-basics/239079: verify the identity
sec^2(x)tan^2(x)+sec^2(x)=sec^4(x)
1 solutions

Answer 175601 by scott8148(3382) About Me  on 2009-11-15 15:24:13 (Show Source):
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dividing by sec^2 ___ tan^2 + 1 = sec^2

multiplying by cos^2 ___ sin^2 + cos^2 = 1


percentage/239025: I really need help on this question:
A goldsmith has two different alloys of gold. One is 50% and one is 75%. A custom necklace requires 200g of 66% gold. How much of each alloy is needed to make this.
1 solutions

Answer 175587 by scott8148(3382) About Me  on 2009-11-15 14:07:30 (Show Source):
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let x="grams of 50%", so 200-x="grams of 75%"

(50%)(x) + (75%)(200 - x) = (66%)(200)


percentage/239022: I need help with this question please..
A goldsmith has two different alloys of gold. One is 50% and one is 75%. A custom necklace requires 200g of 66% gold. How much of each alloy is needed to make this?
1 solutions

Answer 175586 by scott8148(3382) About Me  on 2009-11-15 14:06:30 (Show Source):
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let x="grams of 50%", so 200-x="grams of 75%"

(50%)(x) + (75%)(200 - x) = (66%)(200)


Money_Word_Problems/239006: SEED MIXTURE: a nursery has one kind of grass seed selling at 75 cents per pound and another kind of grass seed selling at $1.10 per pound. How many pounds of each kind should be mixed to produce 50 pounds of a mixture of seed that will sell for 90 cents a pound. I cannot figure out how to work this problem your help would be much appreciated.
1 solutions

Answer 175584 by scott8148(3382) About Me  on 2009-11-15 14:03:31 (Show Source):
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let x="pounds of $.75 seed", so 50-x="pounds of $1.10 seed"

x(.75) + (50 - x)(1.10) = 50(.90)


Square-cubic-other-roots/239009: 2x^2+16x-18
1 solutions

Answer 175583 by scott8148(3382) About Me  on 2009-11-15 13:57:54 (Show Source):
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2(x + 9)(x - 1)


Polynomials-and-rational-expressions/239011: x^2+4x-140
1 solutions

Answer 175582 by scott8148(3382) About Me  on 2009-11-15 13:56:37 (Show Source):
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(x + 14)(x - 10)