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Polynomials-and-rational-expressions/607001: Can the expression a^2-16a+28 be factored. And if so how do I do it?
1 solutions

Answer 382495 by ankor@dixie-net.com(15624) About Me  on 2012-05-04 16:59:34 (Show Source):
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Can the expression a^2-16a+28 be factored. And if so how do I do it?
:
Look at the third term, 28. What are the factors? 2,14 and 4,7, can be both positive or both negative
;
Which of these pairs of factors add up to the coefficient of a, which is -16
-2 - 14 = -16, and we can see that it will be factors of:
:
(a-2)(a-14); FOIL this to check it


Numbers_Word_Problems/607121: the sum of the reciprocal of a number and the reciprocal of 3 less that the number 5 time the reciprocal of the original number. find the original number
1 solutions

Answer 382493 by ankor@dixie-net.com(15624) About Me  on 2012-05-04 16:45:02 (Show Source):
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let x = "a number"
:
Write an equation for the statement:
"the sum of the reciprocal of a number and the reciprocal of 3 less that the number 5 time the reciprocal of the original number."
1%2Fx + 1%2F3 + 3 = 5(1%2Fx)
multiply by 3x, results
1(3) + 1(x) + 3(3x) = 3(5)
:
3 + x + 9x = 15
10x = 15 - 3
10x = 12
x = 12/10
x = 1.2


Mixture_Word_Problems/606963: How many quarts if a 40% alchohol solution must be mixed with 3 quarts of pure water to make a 28% solution?


This is what I am doing but I am getting a negative answer:
(3*1)+(x*.3)=(3+x*.28)
1 solutions

Answer 382491 by ankor@dixie-net.com(15624) About Me  on 2012-05-04 16:29:58 (Show Source):
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How many quarts if a 40% alcohol solution must be mixed with 3 quarts of pure water to make a 28% solution?
:
Let x = amt of 40% solution required
:
.40x = .28(x+3)
.40x = .28x + .84
.40x - .28x = .84
.12x = .84
x = .84/.12
x = 7 quarts of 40% solution required
:
:
Check this
.4(7) = .28(7+3)
2.8 = .28(10)


Human-and-algebraic-language/606887: Mr.lin is four times as old as his daughter. The sum of their ages is twelve years less than twice the difference of their ages. How old is mr.lin? The answer choices are 12,24,36 & 48
1 solutions

Answer 382490 by ankor@dixie-net.com(15624) About Me  on 2012-05-04 16:22:39 (Show Source):
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Mr.lin is four times as old as his daughter.
The sum of their ages is twelve years less than twice the difference of their ages.
How old is mr.lin?
:
Let L = Mr Lin's age
Let d = daughter's age
:
Write an equation for each statement:
:
"Mr.lin is four times as old as his daughter."
L = 4d
:
"The sum of their ages is twelve years less than twice the difference of their ages."
L + d + 12 = 2(L-d)
L + d + 12 = 2L - 2D
d + 2d + 12 = 2L - L
3d + 12 = L
Replace L with 4d (from the 1st statement)
3d + 12 = 4d
12 = 4d - 3d
d = 12 yrs is daughters age
then
4(12) = 48 is Mr Lin's age
:
:
See if that checks out in the statement:
"The sum of their ages is twelve years less than twice the difference of their ages."
48 + 12 + 12 = 2(48 - 12)
72 = 2(36)




test/607026: 5√5x+1 =5√3x
I don't understand .. I'm supposed to solve 4 x.. I need help.. thank you!

1 solutions

Answer 382384 by ankor@dixie-net.com(15624) About Me  on 2012-05-04 09:40:28 (Show Source):
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5√5x+1 = 5√3x
Assuming the problem is:
5sqrt%285x%2B1%29+=+5sqrt%283x%29
:
divide both sides by 5, results:
sqrt%285x%2B1%29+=+sqrt%283x%29
:
Square both sides
5x + 1 = 3x
5x - 3x = -1
2x = -1
x = -1%2F2
:
There is no solution, the value for x gives negative values inside the radicals


Expressions-with-variables/606944: How do i Factor: 3x^2+4xy-6x-8y
1 solutions

Answer 382359 by ankor@dixie-net.com(15624) About Me  on 2012-05-04 08:18:01 (Show Source):
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How do i Factor: 3x^2 + 4xy - 6x - 8y
:
We can group factor here, factor out x, and -2
x(3x + 4y) - 2(3x + 4y)
:
Now factor out (3x+4y) and you have
(3x + 4y)(x - 2); sorry about that!


Equations/606659: Solve square root of 2x+3- square root of x+1=1
1 solutions

Answer 382331 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 21:21:42 (Show Source):
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Solve square root of 2x+3- square root of x+1=1
:
sqrt%282x%2B3%29-sqrt%28x%2B1%29+=+1
:
sqrt%282x%2B3%29+=+sqrt%28x%2B1%29+%2B+1
Square both sides, you have to FOIL the right side
2x + 3 = %28x%2B1%29+%2B+2sqrt%28x%2B1%29+%2B+1
:
2x + 3 = x + 2 + 2sqrt%28x%2B1%29
:
2x - x + 3 - 2 = 2sqrt%28x%2B1%29
:
(x + 1) = 2sqrt%28x%2B1%29
:
Square both sides, FOIL the left side
:
x^2 + 2x + 1 = 4(x+1)
x^2 + 2x + 1 = 4x + 4
x^2 + 2x - 4x + 1 - 4 = 0
x^2 - 2x - 3 = 0
Factors to
(x-3)(x+1) = 0
Two solutions
x = 3
x = -1
;
We have to check both solutions in the original equation
x = -1 will not work, it would give us a neg value inside the radical
Try x = 3
sqrt%286%2B3%29-sqrt%283%2B1%29+=+1; looks OK, x=3 is our solution


Coordinate-system/606648: y=x+4 what is the value of x?

1 solutions

Answer 382328 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 21:09:01 (Show Source):
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y=x+4 what is the value of x?
subtract 4 from both sides
y - 4 = x
or
x = y-4


Travel_Word_Problems/606971: Andy's average driving speed for a 4-hour trip was 45 miles per hour. During the first 3 hours he drove 40 miles per hour. what was his average speed for the last hour of his trip?
1 solutions

Answer 382325 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 20:57:55 (Show Source):
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Andy's average driving speed for a 4-hour trip was 45 miles per hour.
During the first 3 hours he drove 40 miles per hour.
what was his average speed for the last hour of his trip?
:
let s = speed on the last hr
;
Write a distance equation; dist = speed * time
40(3) + 1s = 45(4)
120 + s = 180
s = 180-120
s = 60 mph on the last hr


Equations/606719: Please help me solve this:
2^(4x-3)=1/8
1 solutions

Answer 382321 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 20:48:40 (Show Source):
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solve this:
2%5E%28%284x-3%29%29=1%2F8
log at this, what is 2^-3?. It's 1/8 right?
therefore x = 0


Surface-area/606934: I have a math problem where pi=22/7 and I have to find the area of a circle using pi with a diameter of 5ft 3in. Please show me how to find the area?
1 solutions

Answer 382318 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 20:18:10 (Show Source):
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I have a math problem where pi=22/7 and I have to find the area of a circle using pi with a diameter of 5ft 3in. Please show me how to find the area?
:
Convert 5 ft 3 in to 5.25 ft
This is the diameter, we need the radius: 5.25/2 = 2.625 ft
:
Area of a circle:
A+=+pi%2Ar%5E2
therefore
A = 22%2F7*2.625%5E2; in square ft


Travel_Word_Problems/606591: At noon, car A is 41 miles due west of car B and traveling east at a constant speed of 55 miles an hour. Meanwhile, car B is traveling north at 40 miles per hour. At what time will the two cars be closest to each other? Suggestion, minimize the square of the distance, rather than the distance itself
1 solutions

Answer 382317 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 20:05:45 (Show Source):
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At noon, car A is 41 miles due west of car B and traveling east at a constant speed of 55 miles an hour.
Meanwhile, car B is traveling north at 40 miles per hour.
At what time will the two cars be closest to each other?
:
the relationship between the two cars form a right triangle where
a = (41-55t), car a distance from reference point
b = 40t, car B travel distance from the the same point
c = distance between the cars at t time
:
c^2 = (41-55t)^2 + (40t)^2
c^2 = 1681 - 4510t + 3025t^2 + 1600t^2
c^2 = 4625t^2 - 4510t + 1681
c = sqrt%284625t%5E2+-+4510t+%2B+1681%29
Plot this equation
+graph%28+300%2C+200%2C+-.5%2C+2%2C+-5%2C+50%2C+sqrt%284625x%5E2+-+4510x+%2B+1681%29%29+
looks like they will closest together in half an hour, about 24 miles


percentage/606534: After 4 tests this term Jessica had a 72% average. He has 2 more tests left in the term. What average score will Jessica need on the final 2 tests to bring his average to 80%
1 solutions

Answer 382309 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 19:13:12 (Show Source):
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After 4 tests this term Jessica had a 72% average.
He has 2 more tests left in the term.
What average score will Jessica need on the final 2 tests to bring his average to 80%
:
This means he will have a total of 6 tests
Let x = average grade on the final two tests
:
%28%284%2872%29+%2B+2x%29%29%2F6 = 80
multiply both sides by 6
4(72) + 2x = 6(80)
288 + 2x = 480
2x = 480-284
2x = 192
x = 192/2
x = 96% av on the last two tests


Mixture_Word_Problems/606614: A 5-quart solution of sulfuric acid and water is 60% acid. If a gallon of water is added, what percent of the resulting solution is acid?
A)3%
B)33 1/3%
C)40%
d)48%
E)50%
1 solutions

Answer 382300 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 19:01:47 (Show Source):
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: A 5-quart solution of sulfuric acid and water is 60% acid.
If a gallon of water is added, what percent of the resulting solution is acid?
:
Let x = per cent when a gallon of water is added
:
Change 1 gallon to 4 quarts
:
The amt of acid remains the same
60(5) = x(5 + 4)
300 = 9x
x = 300/9
x = 331%2F3 per cent


Travel_Word_Problems/606488: Suppose a child throws a ball upward and gives it an initial velocity of 10 feet per second. The starting height of the ball is 2.5 feet. How long will it take for the ball to reach its maximum height?
1 solutions

Answer 382227 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 15:33:26 (Show Source):
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Suppose a child throws a ball upward and gives it an initial velocity of 10 feet per second.
The starting height of the ball is 2.5 feet.
How long will it take for the ball to reach its maximum height?
:
The formula for this:
f(t) = -16t^2 + 10t + 2.5
Where
f(t) = height after t time
-16t^2 = force of gravity downward
10t = initial velocity upward
2.5 = initial height of the ball
;
Find the max height, by finding the axis of symmetry: x = -b/(2a)
t = %28-10%29%2F%282%2A-16%29+
t = .3125 sec to reach max height


Trigonometry-basics/606419: an airplane travel at 300 mph is descending at an angle of depression of 6 degrees. How many miles will the plane descend in 2 minutes?
1 solutions

Answer 382191 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 13:19:29 (Show Source):
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an airplane travel at 300 mph is descending at an angle of depression of 6 degrees.
How many miles will the plane descend in 2 minute
:
Find how many miles the plane will travel in 2 min a 300 mph
2%2F60*300 = 10 mi
:
use the sine of 6 degrees, side opposite is the vertical dist (a) of descent
Sin(6) = a%2F10 * 5280 = 5519.1 ft descent


Travel_Word_Problems/606179: a man walks from his home at a speed of 5km/h and returns at a speed of 3km/h what is the distance he walked if the whole trip takes 4 hours
1 solutions

Answer 382172 by ankor@dixie-net.com(15624) About Me  on 2012-05-03 10:51:56 (Show Source):
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a man walks from his home at a speed of 5km/h and returns at a speed of 3km/h what is the distance he walked if the whole trip takes 4 hours
:
Find the time each way first
t = 5 mph time
then
(4-t) = 3 mph time
:
Write a time equation; time = speed * time
:
Go dist = return dist
5t = 3(4-t)
5t = 12 - 3t
5t + 3t = 12
t = 12/8
t = 1.5 hrs
:
Find the distance
5(1.5) = 7.5 mi
check the dist
3(4-1.5) = 7.5 mi


Rational-functions/605939: Could someone please help with this. I have to solve this by the elimination method and I have to show the steps. I am stumped. Please help.
solve by elimination y= 5x-10
2x + 3y=21
Thank you so much for the help!
1 solutions

Answer 381871 by ankor@dixie-net.com(15624) About Me  on 2012-05-01 18:44:30 (Show Source):
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solve this by the elimination method
solve by elimination
y = 5x - 10
2x + 3y = 21
:
Put the 1st equation into standard form also
y = 5x - 10
subtract 5x from both sides
-5x + y = -10
multiply by -3, add to the 2nd equation
15x - 3y = +30
2x + 3y = 21
-----------------adding eliminates y find x
17x = 51
x = 51/17
x = 3
:
Find y using the original 1st equation
y = 5(3) - 10
y = 15 - 10
y = 5
:
The solution is x=3, y=5
:
Confirm this in the 2nd equation
2(3) + 3(5) = 21
6 + 15 = 21


logarithm/605777: Please help me solve this equation:
50e^-0.058x=100
Directions: find exact answer then round to four decimal places.
1 solutions

Answer 381862 by ankor@dixie-net.com(15624) About Me  on 2012-05-01 17:13:36 (Show Source):
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solve this equation:
50e%5E%28-0.058x%29=100
divide both sides by 50
e%5E%28-0.058x%29=100%2F50
:
e%5E%28-0.058x%29=2
nat log of both sides
ln%28e%5E%28-0.058x%29%29=ln%282%29
log equiv of exponents
-.058x%2Aln%28e%29=ln%282%29
ln of e is 1, therefore
-.058x = ln(2)
x = ln%282%29%2F%28-.058%29; using a calc
x = -11.9508




Linear_Equations_And_Systems_Word_Problems/605513: What is the equation that will fit the following information. Gail is raising money by selling popcorn. She rents a cart for 40.00 a day. She sells each box for 1.25 but her expenses for each box is .55. I think this is a y=mx + b equation but I am not sure. Can you help?
1 solutions

Answer 381731 by ankor@dixie-net.com(15624) About Me  on 2012-04-30 21:32:45 (Show Source):
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What is the equation that will fit the following information.
Gail is raising money by selling popcorn. She rents a cart for 40.00 a day.
She sells each box for 1.25 but her expenses for each box is .55.
:
let x = no. of boxes sold
y = amt of money raised
:
y = x(1.25-.55) - 40
y = .70x - 40


Travel_Word_Problems/605484: Stephen has driven 3/5 of the distance from Waco to El Paso. If he has 270miles left to drive, how many miles has he driven?
1 solutions

Answer 381727 by ankor@dixie-net.com(15624) About Me  on 2012-04-30 21:11:28 (Show Source):
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Stephen has driven 3/5 of the distance from Waco to El Paso.
If he has 270 miles left to drive, how many miles has he driven?
:
Find the total distance
If he has driven 3/5, he has 2/5 left, therefore
2%2F5d = 270
2d = 5(270)
d = 675 mi
:
Find no. of miles driven
675 - 270 = 405 mi


Travel_Word_Problems/605269: Biking at 12 mph, it takes Kristen 1/2 hour to reach the train station to go to work. Kristen then takes the train to work, and it takes another 1/2 hour for her to get to work when the train travels 24 mph. How far does Kristen travel to work?
1 solutions

Answer 381719 by ankor@dixie-net.com(15624) About Me  on 2012-04-30 19:57:15 (Show Source):
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Biking at 12 mph, it takes Kristen 1/2 hour to reach the train station to go to work.
Kristen then takes the train to work, and it takes another 1/2 hour for her to get to work when the train travels 24 mph.
How far does Kristen travel to work?
:
Write a distance equation, dist = speed * time
:
Total dist = bike dist + train dist
d = 12(.5) + 24(.5)
d = 6 + 12
d = 18 mi


Mixture_Word_Problems/605138: It took ten men 16 days to paint a house. At that same rate, how many men would it have taken to finish paint the house in 10 days
1 solutions

Answer 381563 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 21:56:04 (Show Source):
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It took ten men 16 days to paint a house.
Find the no. of man-days required to paint the house
10*16 = 160 man-days
:
At that same rate, how many men would it have taken to finish paint the house in 10 days
let m = no. of men required to do it 10 days
10m = 160
m = 160/10
m = 16 men to do it in 10 days


Travel_Word_Problems/604998: Problem: In 2 minutes, a conveyor belt moves 300 pounds of recyclable aluminum from the delivery truck to a storage area. A smaller belt moves the same quantity of cans the same distance in 6 minutes. If both belts are used, find how long it takes to move the cans to the storage area.
I used the following equation:
300/2 + 300/6 = 300/x
My answer is 1.25 minutes.
The book's answer is 1-1/2 minutes. What did I do wrong? Please explain how to set up this problem. Thanks!
1 solutions

Answer 381561 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 21:23:50 (Show Source):
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In 2 minutes, a conveyor belt moves 300 pounds of recyclable aluminum from the delivery truck to a storage area.
A smaller belt moves the same quantity of cans the same distance in 6 minutes.
If both belts are used, find how long it takes to move the cans to the storage area.
:
We can do it this way
let t = time required when both belts are used to move 300 lb
:
Let the completed job = 1 (moving 300 lb)
:
t%2F2 + t%2F6 = 1
Multiply by 6
6*t%2F2 + 6*t%2F6 = 6
Cancel out the denominators
3t + t = 6
4t = 6
t = 6/4
t = 1.5 min


logarithm/605068: how do you solve:
log base 3 (x+4)+log base 3 (x-2)=3
1 solutions

Answer 381556 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 21:02:39 (Show Source):
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log base 3 (x+4)+log base 3 (x-2) = 3
Combine the logs
log3%28%28x%2B4%29%2A%28x-2%29%29+=+3
FOIL
log3%28x%5E2%2B2x-8%29+=+3
the exponent equiv of logs
x%5E2+%2B+2x+-+8+=+3%5E3
:
x%5E2+%2B+2x+-+8+=+27
;
x%5E2+%2B+2x+-+8+-+27+=+0
:
x%5E2+%2B+2x+-+35+=+0
Factors to
(x+7)(x-5) = 0
Two solutions
x = -7
x = 5, since we are dealing with logs, only the positive solution is valid


Linear-systems/605111: Solve the following system of equations for x:
6x+7y=-8
-6x-14y=22
I need your help please. I can't figure out if there is an answer or if these equations represent parallel lines and there is no solution or if these equations represent the same line and there are infinite solutions.
Thank you so much for your help!!
1 solutions

Answer 381553 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 20:52:01 (Show Source):
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6x + 7y = -8
-6x- 14y = 22
--------------adding eliminates x, find y
-7y = 14
y = 14%2F%28-7%29
y = -2
:
Find x using the 1st equation
6x + 7(-2) = -8
6x - 14 = -8
6x = -8 + 14
6x = 6
x = 1
:
:
Check solutions in the 2nd equation
-6(1) - 14(-2) = 22
-6 + 28 = 22


Miscellaneous_Word_Problems/605077: jeff takes 5 hours longer to build a fence than it takes bill. When they work togehter , it takes them 6 hours . How long would it take bill alone to do the job alone?
1 solutions

Answer 381551 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 20:44:55 (Show Source):
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jeff takes 5 hours longer to build a fence than it takes bill.
When they work together, it takes them 6 hours .
How long would it take bill alone to do the job alone?
:
Let b = time required by Bill to build the fence
then
(b+5) = time required by Jeff
:
Let the completed job = 1
:
6%2Fb + 6%2F%28%28b%2B5%29%29 = 1
multiply by b(b+5)
6(b+5) + 6b = b(b+5)
6b + 30 + 6b = b^2 + 5b
0 = b^2 + 5b - 12b - 30
a quadratic equation
b^2 - 7b - 30 = 0
(b-10)(b+3) = 0
The positive solution
b = 10 hrs for Bill to do the job
and
10 + 5 = 15 hrs for Jeff


Polynomials-and-rational-expressions/605058: (x^(3) - x)/(x^(3) + 5x^(2) - 6x) Can you please help me understand how to turn around an expression with negative one and stuff like that, thank you!
1 solutions

Answer 381546 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 20:35:16 (Show Source):
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%28x%5E3+-+x%29%2F%28x%5E3+%2B+5x%5E2+-+6x%29
Factor and cancel x
x%28x%5E2+-+1%29%2Fx%28x%5E2+%2B+5x+-+6%29 = %28x%5E2+-+1%29%2F%28x%5E2+%2B+5x+-+6%29
Factor again, cancel (x-1)
%28%28x-1%29%28x%2B1%29%29%2F%28%28x%2B6%29%28x-1%29%29 = %28x%2B1%29%2F%28x%2B6%29


Money_Word_Problems/604883: the forest service must determine how many acres will be needed to make an addition of twenty-two campsites. if the existing 24-acre campground accommodates fifty-five campsites, how many additional acres will be needed?
1 solutions

Answer 381505 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 15:30:00 (Show Source):
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the forest service must determine how many acres will be needed to make an addition of twenty-two campsites.
if the existing 24-acre campground accommodates fifty-five campsites, how many additional acres will be needed?
:
We can use a ratio equation here. Let a = no. of additional acres required
:
%28%28a%2B24%29%29%2F24 = %28%2822%2B55%29%29%2F55
:
%28%28a%2B24%29%29%2F24 = 77%2F55
Cross multiply
55(a+24) = 24 * 77
55a + 1320 = 1848
55a = 1848 - 1320
55a = 528
a = 528/55
a = 9.6 additional acres required for 22 more campsites


Linear_Equations_And_Systems_Word_Problems/604876: two numbers are related in this way:
the number 1 is subtracted from the first number, the difference is squared, then doubled;the result is equal to the second number. the number 1 is added to the first number, and the sum is squared;the result is equal to 4 minus the second number. determine the numbers.
1 solutions

Answer 381485 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 14:11:04 (Show Source):
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two numbers are related in this way
x & y
:
Step-by-step
the number 1 is subtracted from the first number, the difference is squared,
(x-1)^2
:
then doubled;
2(x-1)^2
;
the result
2(x^2-2x+1) = 2x^2 - 4x + 2
:
is equal to the second number.
2x^2 - 4x + 2 = y
:
the number 1 is added to the first number, and the sum is squared;
(x+1)^2 = x^2 + 2x + 1
:
the result is equal to 4 minus the second number
x^2 + 2x + 1 = 4 - y
x^2 + 2x + 1 - 4 = -y
x^2 + 2x - 3 = -y
2x^2 - 4x + 2 = +y; add the 1st equation
-----------------eliminates y
3x^2 - 2x - 1 = 0
Factors to
(3x+1)(x-1) = 0
Two solutions
x = 1
and
3x = -1
x = -.333
:
find y when x = 1
y = 2(1-1)^2
y = 0
:
Find y when x = -.333
y = 2(-.333-1)^2
y = 2(1.77)
y = 3.54

:


logarithm/604747: log4^n=1/2
1 solutions

Answer 381454 by ankor@dixie-net.com(15624) About Me  on 2012-04-29 10:59:49 (Show Source):
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log4%5En+=+1%2F2
we can write it
n%2Alog%284%29+=+.5
n = .5%2Flog%284%29
using a calc
n = .8305