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Earlsdon answered: 6281 problems
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Inequalities/552693: im trying to graph m<7 on a number line and i cannot figure out if i need to put a closed circle on the 7 or a open circle.
1 solutions

Answer 360468 by Earlsdon(6287) About Me  on 2012-01-04 17:53:50 (Show Source):
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If the number itself is not included (notice the o in not), then use an open circle, otherwise use a closed circle.
m < 7 means m is all numbers that are less than 7 and 7 itself is not less than 7 so 7 is not included. Use an open circle..


Equations/552684: the width of a rectangle is 9x and the length is 3x + 11 solve for x then find the perimeter.

1 solutions

Answer 360466 by Earlsdon(6287) About Me  on 2012-01-04 17:49:03 (Show Source):
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P = 2(L+W) Substitute L = 3x+11 and W = 9x.
P = 2(3x+11+9x) Simplify.
P = 2(12x+11)
P = 24x+22
You can't find the perimeter (P) until you have the value of x.


Numbers_Word_Problems/552678: Five more than three times a number is 23
1 solutions

Answer 360465 by Earlsdon(6287) About Me  on 2012-01-04 17:44:09 (Show Source):
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If n is the number, then:
3n+5 = 23
3n = 18
n = 6


Mixture_Word_Problems/552667: A total of $3000 is invested, part at 2% simple interest and part at 4%. If the total
annual return from the two investments is $100, how much is invested at each
rate?
1 solutions

Answer 360464 by Earlsdon(6287) About Me  on 2012-01-04 17:41:03 (Show Source):
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Let x = the amount invested at 2% while the remainder ($3,000-x) is the amount invested at 4%.
The interest earned on the two amounts can be expressed as:
0.02x and 0.04(3000-x) and the sum of these earnings is $100.00
Here's the equation you'll need to solve for x.
0.02x+0.04(3000-x) = 100 simpify.
0.02x+120-0.04x = 100 Combine the x-terms.
-0.02x+120 = 100 Subtract 120 from both sides.
-0.02x = -20 Finally, divide both sides by -0.02
x = 1000 and 3000-x = 2000
$1000 was invested at 2% and $2000 was invested at 4%


Exponents-negative-and-fractional/552685: I'm not sure how to simplify this fraction:
(8t)^3
------
8t^3
1 solutions

Answer 360462 by Earlsdon(6287) About Me  on 2012-01-04 17:28:45 (Show Source):
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Simplify:
%288t%29%5E3%2F8t%5E3=8%5E3%2At%5E3%2F%288%2At%5E3%29 Cancel the t%5E3's to leave:
8%5E3%2F8 Cancel an 8 to get:
8%5E2+=+64


Polynomials-and-rational-expressions/552011: factoring polynomials
[Sum of cubes]: x^3 + y^3 = (x + y)(x^2 − xy + y^2)
[Difference of cubes]: x^3 - y^3 = (x-y)(x^2 + xy + y^2)
problem:
250x^4-54x
1 solutions

Answer 360020 by Earlsdon(6287) About Me  on 2012-01-02 20:30:00 (Show Source):
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Factor:
250x%5E4-54x Factor 2x.
2x%28125x%5E3-27%29 Now factor the difference of cubes.
2x%28%285x%29%5E3-3%5E3%29
2x%285x-3%29%2825x%5E2%2B15x%2B9%29


test/552003: Factor completely 8x^2 - 98
1 solutions

Answer 360019 by Earlsdon(6287) About Me  on 2012-01-02 20:24:39 (Show Source):
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Factor:
8x%5E2-98 First factor a 2.
2%284x%5E2-49%29 Now factor the binomial, a difference of squares.
2%282x%2B7%29%282x-7%29


Polynomials-and-rational-expressions/551516: Completely factor the expression
147x^2y + 42xy^2 + 3y^3
1 solutions

Answer 359771 by Earlsdon(6287) About Me  on 2012-01-01 19:57:41 (Show Source):
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Factor completely:
147x%5E2y%2B42xy%5E2%2B3y%5E3 Each of the coefficients is divisible by 3y so factor a 3y.
3y%2849x%5E2%2B14xy%2By%5E2%29 The trinomial looks like a perfect square so...
3y%287x%2By%29%287x%2By%29 Check by multiplying the factors.


Equations/551519: simplify
-4^3
1 solutions

Answer 359767 by Earlsdon(6287) About Me  on 2012-01-01 19:50:27 (Show Source):


Polynomials-and-rational-expressions/551518: Completely factor the expression
45x^2 + 150xy + 125y^2
1 solutions

Answer 359764 by Earlsdon(6287) About Me  on 2012-01-01 19:48:26 (Show Source):
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Factor completely:
45x%5E2%2B150xy%2B125y%5E2 First factor a 5 to make it a little easier:
5%289x%5E2%2B30xy%2B25y%5E2%29 The trinomial in the parentheses looks like it might a perfect square, so...
5%283x%2B5y%29%283x%2B5y%29 Check by multiplying these factors.


Equations/551521: write the expression using exponents. do not solve
7.7.7.7.7.7
1 solutions

Answer 359759 by Earlsdon(6287) About Me  on 2012-01-01 19:42:13 (Show Source):
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Is this supposed to be:
7*7*7*7*7*7 If so then = 7%5E6


Equations/551526: simplify
1/0
1 solutions

Answer 359758 by Earlsdon(6287) About Me  on 2012-01-01 19:40:05 (Show Source):
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1%2F0 is undefined!
Division by 0 is not defined in mathematics.


Mixture_Word_Problems/551532: How many liters of a 15% sugar solution should be added to 30 liters of a 25% sugar solution
to obtain a 20% sugar solution? Solve by setting up appropriate equation(s).
1 solutions

Answer 359755 by Earlsdon(6287) About Me  on 2012-01-01 19:36:27 (Show Source):
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Let x = the required number of liters of 15% sugar solution.
The amount of sugar in this solution is 0.15x liters and the amount of sugar in the 30 liters of 25% sugar solution is 0.25(30) liters. When added together you will get a solution containing (30+x)(0.2) liters of sugar. Here's the equation you need:
0.15x+0.25(30) = 0.20(30+x) Solve for x.
0.15x+7.5 = 6+0.2x Subtract 0.15x from both sides.
7.5 = 6+0.05x Subtract 6 from both sides.
1.5 = 0.05x Divide both sides by 0.05
30 = x
30 liters of 15% sugar solution should be added to the 30 liters of 25% sugar solution to obtain 60 liters of 20% sugar solution.


Angles/551531: Two angles are supplementary.If one angle measures twice the other.
1 solutions

Answer 359754 by Earlsdon(6287) About Me  on 2012-01-01 19:21:59 (Show Source):
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Let's say the angles are A and B.
If A and B are supplementary then A+B = 180 degrees.
If angle A = 2B then:
A+B = 180 Substitute A = 2B.
2B+B = 180
3B = 180
B = 60 degrees and A = 2(60) = 120 degrees.


Finance/551533: como se puede saber si el resultado que uno busca es correcto o incorrecto
1 solutions

Answer 359753 by Earlsdon(6287) About Me  on 2012-01-01 19:16:43 (Show Source):
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You have to check your solution by substituting it into the original equation to see if it works.


Equations/551527: translate this to a mathematical equation and solve. please show all of your work
A football team gained 28 yards on one play, lost 33 yards on another, and gained 33 yards on the last play of the first half, they had already gained 207 yards during the half. what was the total yardage gain for the first half?
1 solutions

Answer 359752 by Earlsdon(6287) About Me  on 2012-01-01 19:14:41 (Show Source):
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Remember, a gain is + and a loss is -.
Gained 28 yards = +28
Lost 33 yards = -33
Gained 33 yards = +33
Gained 207 yards = +207 yards.
Add 'em all up.
28-33+33+207 = 28+207 = 235 yards total yardage gained.


test/551412: Jerald has some money in a jar.He says that he has at least $20 and at most $30 in the jar. Let x represent the amount of money in the jar. Write a compound inequality to represent the amount of money in the jar.
1 solutions

Answer 359719 by Earlsdon(6287) About Me  on 2012-01-01 12:35:43 (Show Source):


test/551413: Ball bearings are produced in a factory. A ball bearing is acceptable if its diameter is within 3mm of the target of 50mm.Let x represent the diameter Of a ball bearing. Write an absolute value inequality that represents the range of diameters that are acceptable.
1 solutions

Answer 359718 by Earlsdon(6287) About Me  on 2012-01-01 12:33:30 (Show Source):
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50+3 = 53
50-3 = 47
47%3C=x%3C=53


Travel_Word_Problems/551402: how many gallons you will need to travel 1,150 miles?
1 solutions

Answer 359711 by Earlsdon(6287) About Me  on 2012-01-01 11:34:15 (Show Source):
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Cannot solve this until you say how many miles per gallon.


Equations/551390: 4y+2=-3y-3
1 solutions

Answer 359710 by Earlsdon(6287) About Me  on 2012-01-01 11:32:41 (Show Source):
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Solve:
4y%2B2+=+-3y-3 Add 3y to both sides.
7y%2B2+=+-3 Now subtract 2 from both sides.
7y+=+-5 Finally, divide both sides by 7.
y+=+-5%2F7


Inequalities/551401: My question is how do you solve this inequality please help me
1 solutions

Answer 359709 by Earlsdon(6287) About Me  on 2012-01-01 11:29:26 (Show Source):
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You'll need to post a specific problem to get help!


Travel_Word_Problems/551399: Schools often have a section of street called a school zone located near their entrances. In a school zone, driving speeds are reduced at certain times of the day. If a school zone is 0.3 miles long, how many minutes longer does it take to drive through it at 20 miles per hour that at 30 miles per hour?
1 solutions

Answer 359707 by Earlsdon(6287) About Me  on 2012-01-01 11:17:51 (Show Source):
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Starting with:
d+=+rt d = distance, r = rate/speed, and t = time of travel.
For this problem, we want to find the difference in the times when r = 20mph and r = 30mph over a distance of 0.3 miles.
At 30mph we have:
t%5B1%5D+=+0.3%2F30
t%5B1%5D+=0.01hours.
At 20mph we have:
t%5B2%5D+=+0.3%2F20
t%5B2%5D+=+0.015hours. Subtract t%5B2%5D-t%5B1%5D
0.015-0.01+=+0.005hours. Convert to seconds, multiply by 3600 seconds/hour.
0.005%283600%29+=+18seconds.
It takes 18 seconds longer at 20mph than it would at 30mph.


Inequalities/551400: May you help me with this question it says solve the inequality 4x < 104
1 solutions

Answer 359706 by Earlsdon(6287) About Me  on 2012-01-01 11:05:48 (Show Source):
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Solve:
4x+%3C+104 Solve this inequality just as you would solve a similar equation.
Divid both sides by 4.
x+%3C+26


Travel_Word_Problems/551371: a business man invested part of Php 2,000,000 at 12% and the rest at 15%. if both investments gave him Php250,00 per annum, how much was each investments?
1 solutions

Answer 359705 by Earlsdon(6287) About Me  on 2012-01-01 11:01:35 (Show Source):
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Let's say he invested Php(x) at 12% and the remainder Php(2,000,000-x) at 15%. The earning from these two investments amounts to Php250,000, so we can state this as:
0.12x+0.15(2,000,000-x) = 250,000 Solve for x.
0.12x+300,000-0.15x = 250,000 Simplify.
-0.03x+300,000 = 250,000
-0.03x = -50,000
x = 1,666,666.67 and
2,000,000-x = 333,333.33
The businessman invested Php1,666,666.67 at 12% and Php333,333.33 at 15%


Complex_Numbers/551395: express your answer in simplest a+bi form:
x^2 + 8x + 25 =0
1 solutions

Answer 359704 by Earlsdon(6287) About Me  on 2012-01-01 10:42:38 (Show Source):
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Solve:
x%5E2%2B8x%2B25+=+0 Use the quadratic formula: x+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a where a = 1, b = 8, and c = 25.
x+=+%28-8%2B-sqrt%288%5E2-4%281%29%2825%29%29%29%2F2%281%29 Evaluate:
x+=+%28-8%2B-sqrt%2864-100%29%29%2F2
x+=+%28-8%2B-sqrt%28-36%29%29%2F2
x+=+-4%2B3i or x+=+-4-3i


Geometric_formulas/551398: two lines are parallel if the same side interior angles are_____________ angles.
f. complementary
h. congruent
g. supplementary
j. corresponding

1 solutions

Answer 359703 by Earlsdon(6287) About Me  on 2012-01-01 10:33:45 (Show Source):
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If you were to draw a diagramm of this problem, two parallel lines crossed by a transversal, you would see that the same side interior angles would be supplementary. Try it!


Mixture_Word_Problems/551396: The radiator of a jeep has a capacity of 4 gallons. It is filled with an anti-freeze solution of water and glycol which analyzes 10% glycol. What volume of the mixture must be drawn off and replaced with glycol to obtain a 25% glycol solution? All percentages are by volume. Please thank you~ <3
1 solutions

Answer 359702 by Earlsdon(6287) About Me  on 2012-01-01 10:30:29 (Show Source):
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Think in terms of the amount of glycol in this situation.
Initially you have 4 gallons of solution that is 10% glycol.
The amount of glycol is then 4(0.1) = 0.4 gallons.
You want to remove some of this solution, let's call it x gallons. So we now have:
4(0.1)-x(0.1) of glycol.
Then you want to replace the removed amount of the 10% solution with the same amount of pure (100%) glycol or x(1), so we have:
4(0.1)-x(0.1)+x and this is to equal 4 gallons of 25% glycol solution which is 4(0.25) glycol.
So here's the equation to solve for x.
4(0.1)-x(0.1)+x = 4(0.25) Simplify.
0.4+0.9x = 1
0.9x = 0.6
x = 0.67 gallons.
You must draw off 2%2F3 of a gallon of the 10% solution and replace it with 2%2F3 of a gallon of pure glycol.


Volume/551333: Find the volume, to the nearest tenth, of a pyramid that is 6 feet tall and whose base is an equilateral triangle with sides each 10 feet long.
1 solutions

Answer 359661 by Earlsdon(6287) About Me  on 2011-12-31 21:54:59 (Show Source):
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For a pyramid, the volume is:
V+=+B%2Ah where: B = area of the base and h = the height of the pyramid.
Use Hero's formula to find the area of the triangular base:
A+=+sqrt%28S%28S-a%29%28S-b%29%28S-c%29%29 where S = semi perimeter of the triangle and a, b, and c are the lengths of the sides of the triangle.
A+=+sqrt%2815%2815-10%29%2815-10%29%2815-10%29%29
A+=+sqrt%2815%28125%29%29
A+=+sqrt%281875%29
A+=+43.3
V+=+43.3%286%29
V+=+259.8cu.ft.


test/551284: If the temperature on a Celsius scale is divided by five it is equal to the reading on a Fahrenheit scale. Fifteen times the Fahrenheit reading is equal to three times the Celsius reading. Find the temperature on each scale. Please help me!!!
1 solutions

Answer 359660 by Earlsdon(6287) About Me  on 2011-12-31 21:40:43 (Show Source):


Length-and-distance/551342: Each dimension of a cube has been increased to twice its original size. If the new cube has a volume of 64,000 cubic centimeters, what is the area of one face of the original cube?

1 solutions

Answer 359659 by Earlsdon(6287) About Me  on 2011-12-31 21:29:57 (Show Source):
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Original volume of cube with side = xcm:
V%5B1%5D+=+x%5E3cc.
New volume of cube with side = 2x:
V%5B2%5D+=+%282x%29%5E3 and V = 64,000cc.
64000+=+8x%5E3
x%5E3+=+8000 so...
x+=+20cm.
Area of one face of original cube is:
A+=+x%5E2 x = 20
A+=+400sq.cm.


Length-and-distance/551343: A water tank, having the shape of a rectangular prism of base 100 square centimeters, is being filled at the rate of 1 liter per minute. Find the rate at which the height of the water in the water tank increases. Express your answer in centimeters per minute.

1 solutions

Answer 359655 by Earlsdon(6287) About Me  on 2011-12-31 21:21:40 (Show Source):
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Start with:
1 liter = 1,000cc
The area of the bottom of the tank is 100cm.
If you now put in enough water to raise the level 10cm, you would have 10X100 = 1,000cc of water which is just 1 liter of water.
So adding 1 liter of water to this tank raises the level 10cm.
Hence, if the tank is being filled at the rate of 1 liter (1,000cc) per minute, the water level will rise at the rate of 10cm per minute.