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Alan3354 answered: 31511 problems
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Volume/362719: can you help please?? I have a question and I need the formula and the answer:
find the volume of a sphere with a diameter of 6.3cm thanks
1 solutions

Answer 258516 by Alan3354(31532) About Me  on 2010-10-27 18:28:38 (Show Source):
You can put this solution on YOUR website!
The formula is
Vol+=+4%2Api%2Ar%5E3%2F3
r = d/2 = 3.15 cm
Sub r into the formula to get the volume.


Expressions-with-variables/362621: A truck traveling at a constant rate of 45 miles per hour leaves Albany. One hour later a car traveling at a constant rate of 60 miles per hour also leaves Albany traveling in the same direction of the same highway. How long will it take for the car to catch up to the truck if both vehicles continue in the same direction on the highway? I do not understand can u please help?
1 solutions

Answer 258501 by Alan3354(31532) About Me  on 2010-10-27 17:50:51 (Show Source):
You can put this solution on YOUR website!
A truck traveling at a constant rate of 45 miles per hour leaves Albany. One hour later a car traveling at a constant rate of 60 miles per hour also leaves Albany traveling in the same direction of the same highway. How long will it take for the car to catch up to the truck if both vehicles continue in the same direction on the highway?
-----------
In 1 hour, the 1st truck has gone 45 miles.
The 2nd truck gains on it at 15 mph (60 - 45)
45/15 = 3 hours
------------
That's 3 hours after the car leaves, 4 hours after the truck has left.


Polynomials-and-rational-expressions/362700: I need help with a couple more problems.
Factor check by mulitplying:
x^4-8x^3
Multiply:
(7-x)(9-2x)
1 solutions

Answer 258499 by Alan3354(31532) About Me  on 2010-10-27 17:47:42 (Show Source):
You can put this solution on YOUR website!
What sort of help?


Linear-equations/362704: I'm having a problem finding the slope -10x+6y=-30
1 solutions

Answer 258497 by Alan3354(31532) About Me  on 2010-10-27 17:46:46 (Show Source):
You can put this solution on YOUR website!
Solve for y
-10x+6y=-30
-5x + 3y = -15
3y = 5x - 15
y = (5/3)x - 5
---------
The slope is the coefficient of x
m = 5/3
That's all.


Numeric_Fractions/362701: i dont know how to get the answer to problems like this: x/5-2/7 can u explain how? thank u
1 solutions

Answer 258496 by Alan3354(31532) About Me  on 2010-10-27 17:44:59 (Show Source):
You can put this solution on YOUR website!
What is the problem?
What do you want to do?


Graphs/362646: x=8 graph the equation by plotting points
1 solutions

Answer 258458 by Alan3354(31532) About Me  on 2010-10-27 16:21:18 (Show Source):
You can put this solution on YOUR website!
For all y values, x = 8
-------------
(8,0)
(8,8)
(8,-8)
(8,1000)


Travel_Word_Problems/362543: An elderly wildebeest scents a lion and starts running away at 40mph. .02 hours later (about 1 minute) the lion starts running after the wildebeest at 50 mph. Presuming the lion and the wildebeest started from the same spot, how long will it take the lion to catch the wildebeest?
1 solutions

Answer 258425 by Alan3354(31532) About Me  on 2010-10-27 14:29:14 (Show Source):
You can put this solution on YOUR website!
An elderly wildebeest scents a lion and starts running away at 40mph. .02 hours later (about 1 minute) the lion starts running after the wildebeest at 50 mph. Presuming the lion and the wildebeest started from the same spot, how long will it take the lion to catch the wildebeest?
-----------------
In 0.02 hours the wildebeest will be 0.8 miles away (40*0.02)
The lion gains on him at 10 mph (50 - 40)
0.8/10 = 0.08 hours
= 4.8 minutes
===============
A different method:
They will travel the same distance.
For the wb: d = 40(t + 0.02)
For the lion: d = 50t
50t = 40(t + 0.02)
50t = 40t + 0.8
10t = 0.8
t = 0.08 hours
t = 4.8 minutes.
-----------------
The other tutor got 6 minutes, but that's the time the wb was running, not the time the lion was chasing it.


Quadratic_Equations/362564: A friend of mine told me that if you need help with algebra this was the website to submit your question. I am confused on what steps to take the get the final answer. If someone could be so kind as to show me what to do, I would be appreciate it. I know it's time consuming, but could you please work the problem in all vital steps (maybe with some direction) so I know how to complete the next series that I have to do for my assignment?
11.4, #9
Directions: Solve the equation by making an appropriate substitution.
x^(-2)+〖8x〗^(-1)=-10 (should be x - squared, and 8x to -1 power)

1 solutions

Answer 258417 by Alan3354(31532) About Me  on 2010-10-27 14:10:43 (Show Source):
You can put this solution on YOUR website!
(should be x - squared, and 8x to -1 power)
----------------------
x%5E-2+%2B+8x%5E-1+=+-10
-----------
Sub y for x^-1
y%5E2+%2B+8y+%2B+10+=+0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B8x%2B10+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%288%29%5E2-4%2A1%2A10=24.

Discriminant d=24 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-8%2B-sqrt%28+24+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%288%29%2Bsqrt%28+24+%29%29%2F2%5C1+=+-1.55051025721682
x%5B2%5D+=+%28-%288%29-sqrt%28+24+%29%29%2F2%5C1+=+-6.44948974278318

Quadratic expression 1x%5E2%2B8x%2B10 can be factored:
1x%5E2%2B8x%2B10+=+%28x--1.55051025721682%29%2A%28x--6.44948974278318%29
Again, the answer is: -1.55051025721682, -6.44948974278318. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B8%2Ax%2B10+%29

----------------
The solutions shown are for y.
y = -4 ± sqrt(6)
1/x = = -4 ± sqrt(6)
---------------------
x = 1/(-4 + sqrt(6))
x = (-4 - sqrt(6))/(16 - 6)
x = (-4 ± sqrt(6))/10
=========================
Substitution is not the best method, tho.
x%5E-2+%2B+8x%5E-1+=+-10
Multiply thru by x^2
1+%2B+8x+=+-10x%5E2
10x%5E2+%2B+8x+%2B+1+=+0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 10x%5E2%2B8x%2B1+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%288%29%5E2-4%2A10%2A1=24.

Discriminant d=24 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-8%2B-sqrt%28+24+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%288%29%2Bsqrt%28+24+%29%29%2F2%5C10+=+-0.155051025721682
x%5B2%5D+=+%28-%288%29-sqrt%28+24+%29%29%2F2%5C10+=+-0.644948974278318

Quadratic expression 10x%5E2%2B8x%2B1 can be factored:
10x%5E2%2B8x%2B1+=+%28x--0.155051025721682%29%2A%28x--0.644948974278318%29
Again, the answer is: -0.155051025721682, -0.644948974278318. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+10%2Ax%5E2%2B8%2Ax%2B1+%29

----------------
Simpler, less work, less time.


Graphs/362537: Graph the equation and identify the Y-intercept Y=1/2x.
My biggest problem is i dont understand how we get a value to substitute for x.
1 solutions

Answer 258414 by Alan3354(31532) About Me  on 2010-10-27 14:02:40 (Show Source):
You can put this solution on YOUR website!
The y-axis is crossed when x=0.


Graphs/362540: -x+5y=10 Use the intercepts to graph the equation.
Same problem i dont know what to do to come up with substitutes for x and y.
1 solutions

Answer 258409 by Alan3354(31532) About Me  on 2010-10-27 13:56:02 (Show Source):
You can put this solution on YOUR website!
You sub zero for x to find the y-intercept.
Sub zero for y to find the x-intercept.


Graphs/362539: 3x-9=3y Use intercepts to graph equation.
Same problem i dont know what to do to come up with substitutes for x and y.
1 solutions

Answer 258402 by Alan3354(31532) About Me  on 2010-10-27 13:47:28 (Show Source):
You can put this solution on YOUR website!
3x-9=3y Use intercepts to graph equation.
----------
At the x-intercept y = 0
3x - 9 = 0
x = 3 --> (3,0)
----------------
At the y-intercept x = 0
-9 = 3y
y = -3 --> (0,-3)
--------------
Plot the 2 points, draw a line thru them.


Graphs/362541: 4=x+2 Graph the equation and Identify the y-intercept.
Just lost on the problem all together.
1 solutions

Answer 258399 by Alan3354(31532) About Me  on 2010-10-27 13:44:19 (Show Source):
You can put this solution on YOUR website!
4=x+2
x = 2
The graph is parallel to the y-axis 2 units to the positive side.
There is no y-axis intercept since they're parallel.


Equations/362505: An airplane flies from New Orleans, Louisiana, to Atlanta, Georgia, at an average rate of 320 miles per hour. The airplane then returns at an average rate of 280 miles per hour. The total travel time is 3 hours. How long did it take to fly from New Orleans to Atlanta?

1 solutions

Answer 258377 by Alan3354(31532) About Me  on 2010-10-27 12:03:02 (Show Source):
You can put this solution on YOUR website!
d = distance in miles one way
--------
d/320 + d/280 = 3
15d/2240 = 3
15d = 6720
d = 448 miles
------------
448/320 = 1.4 hours


Conjunction/362497: I have been trying to help you.
how we can this sentence make disjunctiv question
1 solutions

Answer 258375 by Alan3354(31532) About Me  on 2010-10-27 11:45:54 (Show Source):
You can put this solution on YOUR website!
Help me do what?


logarithm/362504: Hi
My question is this expression:
80-15log10(t+1)=78
Im confused on how to solve this. Can u help as soon as possible?
1 solutions

Answer 258373 by Alan3354(31532) About Me  on 2010-10-27 11:44:03 (Show Source):
You can put this solution on YOUR website!
80-15log10(t+1)=78
----------
That's not a question, it's an equation.
I'll assume you want to solve for t.
--------------
80-15log10(t+1)=78
15log(t+1) = 2
log(t+1) = 2/15
t%2B1+=+10%5E%282%2F15%29
t+1 =~ 1.359356
t =~ 0.359356


Graphs/362490: find the midpoint of the line between two points (10,4)(2,6)
1 solutions

Answer 258367 by Alan3354(31532) About Me  on 2010-10-27 11:12:32 (Show Source):
You can put this solution on YOUR website!
Find the average of x and y separately.
x: (10 + 2)/2 = 6
y: (4 + 6)/2 = 5
midpoint at (6,5)


Trigonometry-basics/362483: How do I find the period of the function f(x)=cos(1/2)x?
1 solutions

Answer 258362 by Alan3354(31532) About Me  on 2010-10-27 10:58:28 (Show Source):
You can put this solution on YOUR website!
If you mean cos(x/2) it's 4pi.
----------
The period of a trig function f(x) is 2pi radians, or 360 degs.
The period of sin(ax) is 2pi/a radians.


Circles/362472: A circle measures 8 feet in diameter. What's its area to the nearest foot?
1 solutions

Answer 258341 by Alan3354(31532) About Me  on 2010-10-27 09:45:26 (Show Source):
You can put this solution on YOUR website!
Area+=+pi%2Ar%5E2+=+16pi
Use a calculator. Round to the nearest square foot, not foot.


Travel_Word_Problems/362477: Sue and Joe are opposite side of a circular lake that is 1260 feet in circumference. They walk around it, starting at the same time and walking in the same direction. Sue walks at the rate of 50 yards a minute and Joe walks at the rate of 60 yards a minute. In how many minutes will Joe overtake Sue?
1 solutions

Answer 258338 by Alan3354(31532) About Me  on 2010-10-27 09:39:01 (Show Source):
You can put this solution on YOUR website!
Sue and Joe are opposite side of a circular lake that is 1260 feet in circumference. They walk around it, starting at the same time and walking in the same direction. Sue walks at the rate of 50 yards a minute and Joe walks at the rate of 60 yards a minute. In how many minutes will Joe overtake Sue?
-------------
1260 feet = 420 yards
1/2 of that = 210 yards
--------------
Joe gains on Sue at 10 yds/min (60-50)
210/10 = 21 minutes


Exponential-and-logarithmic-functions/362349: +2%5E%282x-3%29+=+5%5E%28-x-1%29+
1 solutions

Answer 258325 by Alan3354(31532) About Me  on 2010-10-27 09:14:49 (Show Source):
You can put this solution on YOUR website!
+2%5E%282x-3%29+=+5%5E%28-x-1%29+
(2x-3)*log(2) = (-x-1)*log(5)
2x*log(2) - 3log(2) = -xlog(5) - log(5)
2log(2) = log(4) and 3log(2) = log(8)
-------------------------------------
x*log(4) + x*log(5) = log(8) - log(5)
x(log(4) + log(5)) = log(1.6)
x*log(20) = log(1.6)
x = log(1.6)/log(20)
x =~ 0.678072


logarithm/362301: how do you graph 2-log base5 of(x)
1 solutions

Answer 258186 by Alan3354(31532) About Me  on 2010-10-26 21:13:53 (Show Source):
You can put this solution on YOUR website!
y+=+2log%285%2Cx%29
Use the base change method:
y = 2log(x)/log(5)
--------------
Pick values of x and find y. Plot the points, draw a curve thru them.
You can use Excel to do the calculations.
Or dl the FREE graph software at
http://www.padowan.dk.com


Volume/362210: How do i convert 1660 sec. to hrs.
1 solutions

Answer 258133 by Alan3354(31532) About Me  on 2010-10-26 19:40:47 (Show Source):
You can put this solution on YOUR website!
1 hour = 3600 seconds
Divide it by 3600


Quadratic-relations-and-conic-sections/362223: Find the zeros of the quadratic function
y= x^2-x-12
1 solutions

Answer 258132 by Alan3354(31532) About Me  on 2010-10-26 19:38:16 (Show Source):
You can put this solution on YOUR website!
y= x^2-x-12
----------
x%5E2+-+x+-+12+=+0
(x-4)(x+3) = 0
etc


Equations/362225: y=-3x+9
how do I begin

1 solutions

Answer 258130 by Alan3354(31532) About Me  on 2010-10-26 19:32:45 (Show Source):
You can put this solution on YOUR website!
It depends on what you want to do.


Probability-and-statistics/362220: If a company is randomly selected from the list of 20 studied, what is the probability:
1 solutions

Answer 258129 by Alan3354(31532) About Me  on 2010-10-26 19:28:14 (Show Source):
You can put this solution on YOUR website!
Probability of what?
If it's selected, it's 100%
If a company is to be selected from 20, it's 1 of 20 = 0.05


Percentage-and-ratio-word-problems/362026: A gasoline tank is 1/4 full. After adding 10 gallons of gas, the gauge indicates that the tank is 2/3 full. What is the capacity of the tank in gallons?
1 solutions

Answer 258077 by Alan3354(31532) About Me  on 2010-10-26 16:04:15 (Show Source):
You can put this solution on YOUR website!
A gasoline tank is 1/4 full. After adding 10 gallons of gas, the gauge indicates that the tank is 2/3 full. What is the capacity of the tank in gallons?
--------
10 gallons = (2/3) - (1/4) tank
10 gal = 5/12 tank
tank = 10/(5/12) = 24 gallons


Trigonometry-basics/362063: Its a fraction so please help. I need it fast.
1/m+1/n
Over 1
Over 1/m^2 - 1/n^
1 solutions

Answer 258075 by Alan3354(31532) About Me  on 2010-10-26 16:01:17 (Show Source):
You can put this solution on YOUR website!
Is that 1 problem or 3?
What is n^ ??


Expressions-with-variables/362064: what is the difference between x-3 and 3-x?
1 solutions

Answer 258070 by Alan3354(31532) About Me  on 2010-10-26 15:52:24 (Show Source):
You can put this solution on YOUR website!
the difference is either 2x - 6 or 6 - 2x.
-----------
3-x = -(x-3)


Travel_Word_Problems/362045: You leave your home going 40 mph and arrive at work 1 minute late.
the next day you leave your home going 45 mph and arrive 1 minute early.
Question: How far away is your work?
1 solutions

Answer 258066 by Alan3354(31532) About Me  on 2010-10-26 15:48:40 (Show Source):
You can put this solution on YOUR website!
40 mph = 2/3 mi/minute
45 mph = 3/4 mi/minute
The difference in time is 2 minutes.
----------------
d/(3/4) = d/(2/3) - 2
4d/3 = 3d/2 - 2 = (3d-4)/2
8d = 3(3d-4) = 9d - 12
d = 12 miles
-------------
12 miles @ 40 mph --> 18 minutes
12 miles @ 45 mph --> 16 minutes


logarithm/362034: how do I find the answer to Log(base 1/2)4?
1 solutions

Answer 258053 by Alan3354(31532) About Me  on 2010-10-26 14:52:49 (Show Source):
You can put this solution on YOUR website!
You can always use the base change:
= log(4)/log(1/2)
= -2


Quadratic_Equations/362029: I am having a problem grasping the factoring of quadratic equations. I have an example 3x^2+18x+25=0 Now from what I understand I am suppose to find two numbers that add up to 25 that also make 18 or so I thought. I am confused is there anyways to simplify this for me. I understand once I figure out this how to plug in the numbers for the x=-b sqrt of b^-4ac over 2a to get my answers
1 solutions

Answer 258045 by Alan3354(31532) About Me  on 2010-10-26 14:17:58 (Show Source):
You can put this solution on YOUR website!
That's not factorable using integers.
----------------
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 3x%5E2%2B18x%2B25+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%2818%29%5E2-4%2A3%2A25=24.

Discriminant d=24 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-18%2B-sqrt%28+24+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2818%29%2Bsqrt%28+24+%29%29%2F2%5C3+=+-2.18350341907227
x%5B2%5D+=+%28-%2818%29-sqrt%28+24+%29%29%2F2%5C3+=+-3.81649658092773

Quadratic expression 3x%5E2%2B18x%2B25 can be factored:
3x%5E2%2B18x%2B25+=+%28x--2.18350341907227%29%2A%28x--3.81649658092773%29
Again, the answer is: -2.18350341907227, -3.81649658092773. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+3%2Ax%5E2%2B18%2Ax%2B25+%29