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Rectangles/546032: There is a question I'm stuck on it says the car is 8ft long and a model is 7inches long how can I find the ratio of the length of the car to the length of the mode.... please help
1 solutions

Answer 355833 by ankor@dixie-net.com(15623) About Me  on 2011-12-12 15:21:19 (Show Source):
You can put this solution on YOUR website!
the car is 8 ft long and a model is 7 inches long how can I find the ratio of the length of the car to the length of the mode...
:
To compare we need both items in the same units
:
Car: Model; (12*8):7 = 96:7


logarithm/545712: HI I'm trying to solve this equation and am facing immense difficulty, log base5(sqrt 125)=x. Thank you for your help it is very much appreciated.

1 solutions

Answer 355818 by ankor@dixie-net.com(15623) About Me  on 2011-12-12 14:06:39 (Show Source):
You can put this solution on YOUR website!
log base5(sqrt 125)= x
write the exponent equiv of logs
5%5Ex+=+sqrt%28125%29
Square both sides
5%5E%282x%29+=+125
using common logs
log%28%285%5E%282x%29%29%29+=+log%28%28125%29%29
which is
2x * log(5) = log(125)
2x = log%28125%29%2Flog%285%29
use a calc
2x = 3
x = 1.5
:
:
check this on a calc
enter 5^1.5 = 11.18
enter sqrt%28125%29 = 11.18




Travel_Word_Problems/545857: Two motorists A and B race around a circular mile track starting at the same positions and at the same time. When traveling in the opposite, they are together every 18 seconds, and when traveling in the same direction, they are together every 90 seconds. Find their speeds in mph.
1 solutions

Answer 355810 by ankor@dixie-net.com(15623) About Me  on 2011-12-12 13:46:31 (Show Source):
You can put this solution on YOUR website!
Two motorists A and B race around a circular mile track starting at the same positions and at the same time.
When traveling in the opposite, they are together every 18 seconds, and when traveling in the same direction, they are together every 90 seconds.
Find their speeds in mph.
:
Let a = speed of A
Let b = speed of B
:
They want the answer in mph, change seconds to hours
18%2F3600 = .005 hrs
90%2F3600 = .025 hrs
:
write a distance equation for each scenario
.005(a + b) = 1, (opposite directions)
.025(a - b) = 1, (same direction)
:
In each equation: divide both sides by .005, divide the 2nd equation by .025, results:
a + b = 200
a - b = 40
------------adding eliminates b, find a
2a = 240
a = 240/2
a = 120 mph for A
and
a + b = 200
120 + b = 200
b = 200 - 120
b = 80 mph for B


Quadratic-relations-and-conic-sections/545970: I don't understand this problem confused it asked to solve the quadratic equation by completing the statement.
x2^-14x=-45
1 solutions

Answer 355798 by ankor@dixie-net.com(15623) About Me  on 2011-12-12 13:18:42 (Show Source):
You can put this solution on YOUR website!
solve the quadratic equation by completing the statement.
x^2 - 14x = -45
I think they may mean by "completing the square"
x^2 - 14x + ____ = -45
To complete the square, we divide the coefficient of x by 2 and square it
That would be 14/2 = 7, 7^2 = 49, so we have
x^2 - 14x + 49 = -45 + 49, we have to add 49 to both sides
x^2 - 14x + 49 = 4
Which is
(x-7)^2 = 4
Find the square root of both sides
x - 7 = +/- sqrt%284%29
x - 7 = +/- 2
Two solutions
x = 7 + 2
x = 9
and
x = 7 - 2
x = 5


Age_Word_Problems/545765: Jamar is four times as old as Pam , who is one-third as old as jackie. if jackie is 18 , what is the sum of their age ? how to write the equation ?
1 solutions

Answer 355774 by ankor@dixie-net.com(15623) About Me  on 2011-12-12 10:12:47 (Show Source):
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Jamar is four times as old as Pam,
jr = 4p
:
who is one-third as old as jackie.
p = 1%2F3ja
or
ja = 3p
:
if jackie is 18,
ja = 18
Therefore
3p = 18
p = 6 yrs is Pam's age
and
jr = 4p
therefore
jr = 24 yrs is Jamar's age
:
what is the sum of their age?
24 + 6 + 18 = 48


:


Average/545784: What is the number grade that I need to get on my final exam to end up with a 72 overall in the class, if I currently have a 86 in the class and the final is worth 30% of my grade.
1 solutions

Answer 355761 by ankor@dixie-net.com(15623) About Me  on 2011-12-12 08:49:37 (Show Source):
You can put this solution on YOUR website!
What is the number grade that I need to get on my final exam to end up with a 72 overall in the class, if I currently have a 86 in the class and the final is worth 30% of my grade.
:
We can do it this way,
Let x = the final exam grade to have 72 average
%28%287%2886%29+%2B+3x%29%29%2F10 = 72
multiply both sides by 10
602 + 3x = 720
3x = 720 - 602
3x = 118
x = 118%2F3
x = 39.3 %, you should be able to handle that, right?


Functions/545645: Let f(x)= -2x^2 +4x +5
(a) find the vertex
(b) find the leading co-efficient
(c) what is the shape of the graph?
(d) what is the axis of symmetry?
Thank you in advance for your assistance! I appreciate it and I look forward to seeing your answer.
1 solutions

Answer 355758 by ankor@dixie-net.com(15623) About Me  on 2011-12-12 08:40:56 (Show Source):
You can put this solution on YOUR website!
f(x)= -2x^2 + 4x + 5
:
y = -2x^2 + 4x + 5
(a) find the vertex
Use the axis of symmetry to find the vertex, the formula for that x = -b/(2a)
x = %28-4%29%2F%282%2A-2%29
x = 1
Find y when x=1
y = -2(1^2) + 4(1) + 5
y = 7
the vertex: 1,7
:
(b) find the leading co-efficient
That's the coefficient of x^2 which is -2
:
(c) what is the shape of the graph?
A parabola, opening downward, the vertex is the maximum
:
(d) what is the axis of symmetry? See a


Age_Word_Problems/545562: your math teacher told me that this year she is three times as old as her little sister. However, six years ago she was five times as old as her sister. How old is your math teacher now?
1 solutions

Answer 355678 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 21:52:58 (Show Source):
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let t = teacher's age now
let s = sister's age
:
"This year she is three times as old as her little sister."
t = 3s
:
"However, six years ago she was five times as old as her sister."
t -6 = 5(s - 6)
t - 6 = 5s - 30
t = 5s - 30 + 6
t = 5s - 24
From the 1st statement, replace t with 3s
3s = 5s - 24
24 = 5s - 3s
24 = 2s
s = 24/2
s = 12 yr is sisters present age
then
3(12) = 36 yrs is teacher's age
:
:
Check solution in the statement:
"six years ago she was five times as old as her sister."
36 - 6 = 5(12 - 6)
30 = 5(6); confirms our solution





Money_Word_Problems/545642: The half life of stontium-90 is 28 years. How long will it take a 50 mg sample to decay to a mass of 32 mg?
1 solutions

Answer 355676 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 21:40:55 (Show Source):
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The half life of stontium-90 is 28 years.
How long will it take a 50 mg sample to decay to a mass of 32 mg?
:
Using the half-life formula: A = Ao*2^(-t/h), where
A = resulting amt after t time
Ao = initial amt
t = decay time
h = half-life of substance
:
50*2^(-t/28) = 32
2^(-t/28) = 32%2F50
2^(-t/28) = .64
Using nat logs
ln(2^(-t/28)) = ln(.64)
log equiv of exponents
-t%2F28*ln(2) = ln(.64)
-t%2F28 = ln%28.64%29%2Fln%282%29
-t%2F28 = -.643856
t = -.64356) * -28
t ~ +18 years
:
:
Check on your calc: enter 50*2^(-18/28) results: 32.0



Miscellaneous_Word_Problems/545564: Debbie traveled by boat 5 miles upstream to fish in her favorite spot. Because of the 6-mph current, it took her 40 minutes longer to get there than to return. How fast will her boat go in still water? (Please round your answer to one decimal place.)
1 solutions

Answer 355670 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 21:24:53 (Show Source):
You can put this solution on YOUR website!
Debbie traveled by boat 5 miles upstream to fish in her favorite spot.
Because of the 6 mph current, it took her 40 minutes longer to get there
than to return.
How fast will her boat go in still water?
:
Let s = boat speed in still water
then
(s-6) = speed upstream
and
(s+6) = speed down stream
:
Convert 40 min to hrs: 40/60 = 2%2F3hr
:
Write a time equation: time = distance%2Fspeed

Upstream time = downstream time + 40 minutes (2/3 hr)
5%2F%28%28s-6%29%29 = 5%2F%28%28s%2B6%29%29 + 2%2F3
:
To clear out these denominators, multiply equation by 3(s+6)(s-6)
3(s+6)(s-6)*5%2F%28%28s-6%29%29 = 3(s+6(s-6)*5%2F%28%28s%2B6%29%29 + 2%2F3*3(s+6)(s-6)
Results in
:
15(s+6) = 15(s-6) + 2(s+6)(s-6)
:
15s + 90 = 15s - 90 + 2(s^2 - 36)
:
15s + 90 = 15s - 90 + 2s^2 - 72
:
0 = 15s - 15s - 90 - 90 + 2s^2 - 72
:
2s^2 - 252 = 0
:
2s^2 = 252
Divide by 2
s^2 = 126
s = sqrt%28126%29
s = 11.225 mph speed in still water
:
:
Check solution on calc: (speed up = 5.225 and speed down = 17.225)
5/5.225 - 5/17.225 = .6667 which is 2/3 of an hr





Polynomials-and-rational-expressions/545438: Please help me. The question says to add and simplify when possible. [8z/(z^2-1)]+z/(z-1). Any help would be greaty appreciated.
1 solutions

Answer 355658 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 20:59:30 (Show Source):
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%288z%29%2F%28z%5E2-1%29 + z%2F%28z-1%29
Note the z^2 - 1, is the difference of squares, and can be factored to:
%288z%29%2F%28%28z-1%29%28z%2B1%29%29 + z%2F%28z-1%29
this will be our common denominator and we have
%288z+%2B+z%28z%2B1%29%29%2F%28%28z-1%29%28z%2B1%29%29 = %288z+%2B+z%5E2%2Bz%29%2F%28%28z-1%29%28z%2B1%29%29 = %28z%5E2+%2B+9z+%29%2F%28%28z-1%29%28z%2B1%29%29


Quadratic_Equations/545464: factor completely: a^2p^2 + q^2-p^2 - a^2q^2





thank you
1 solutions

Answer 355648 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 20:47:43 (Show Source):
You can put this solution on YOUR website!
factor completely:
a%5E2p%5E2+%2B+q%5E2-p%5E2+-+a%5E2q%5E2
Re group this as follows
%28a%5E2p%5E2+-+p%5E2%29%2B%28q%5E2+-+aq%5E2%29
factor out the common term
p%5E2%28a%5E2+-+1%29+%2B+q%5E2%281+-+a%5E2%29
We want to change the sign of (1 - a^2), so change the sign of q^2, and we have
p%5E2%28a%5E2+-+1%29+-+q%5E2%28a%5E2+-+1%29
Factor out (a^2 - 1) and we have
%28a%5E2-1%29%28p%5E2-q%5E2%29


Proportions/545454: how do you solve this.you are 5.5feet tall and cast a 3foot shadow.Your office building cast a 40foot shadow.How tall is the building
1 solutions

Answer 355629 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 19:37:35 (Show Source):
You can put this solution on YOUR website!
how do you solve this.you are 5.5feet tall and cast a 3
foot shadow.Your office building cast a 40foot shadow.
How tall is the building
:
We can use proportion here, let x = height of the building
x%2F5.5 = 40%2F3
Cross multiply
3x = 5.5 * 40
3x = 220
x = 220%2F3
x = 731%2F3 ft


Angles/545490: Imagine a triangle which contains angles A,B, and C. If the sum of the measures of A and B is 115 degrees what is the measure of C?
I have no idea how to figure that out can you teach me how I would do this kind of a problem so I can know for future reference? If you can help I would GREATLY appreciate it thank you so very much for your time and help!
1 solutions

Answer 355613 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 18:17:55 (Show Source):
You can put this solution on YOUR website!
Imagine a triangle which contains angles A, B, and C.
If the sum of the measures of A and B is 115 degrees what is the measure of C?
:
A + B + C = 180
:
The sum of A + B was given as 115, therefore, we can write it
115 + C = 180
Subtract 115 from both sides
C = 180 - 115
C = 65 degrees


Mixture_Word_Problems/545041: A mechanic has 341 gallons of gasoline and 18 gallons of oil to make gas/oil mixtures. He wants one mixture to be 8% oil and the other mixture to be 3.5% oil. If he wants to use all of the gas and oil, how many gallons of gas and oil are in each of the resulting mixtures?
i know that:
mixture A = oil/(oil+gas)=.08
mixture B = oil/(oil+gas)=.035
if i mix all the gas and oil together i get a 5.013% soulution.
it's supposed to be a system of equations problem.. but my answer document has four blanks to fill in because there are two mixtures, but i cannot figure out how i would even go about this problem.
1 solutions

Answer 355587 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 15:40:39 (Show Source):
You can put this solution on YOUR website!
A mechanic has 341 gallons of gasoline and 18 gallons of oil to make gas/oil mixtures.
He wants one mixture to be 8% oil and the other mixture to be 3.5% oil.
If he wants to use all of the gas and oil, how many gallons of gas and oil are in each of the resulting mixtures?
:
let a = amt of mixture which is 8% oil
let b = amt of mixture which is 3.5% oil
:
The oil equation
.08a + .035b = 18
the gas equation
.92a + .965b = 341
:
Multiply the 1st equation by 23, multiply the 2nd equation by 2
1.84a + .805b = 414
1.84a + 1.93b = 682
---------------------subtraction eliminates a, find b
-1.125b = -268
b = %28-268%29%2F%28-1.125%29
b = +238.2 gal of the 3.5% mixture
then
.035(238.2) = 8.337 gal of oil in the 3.5% mixture
and
.965(238.2) = 229.863 gal of gas int he 3.5% mixture
:
How about the 8% mixture?
18 - 8.337 = 9.663 gal of oil in the 8% mixture
and
341 - 229.863 = 111.137 gal of gas in the 8% mixture


Rate-of-work-word-problems/545003: Tom and Jack are shingling a roof. Tom takes 75% of the time Jack does to shingle a roof. Together they finish the roof in 5 hours. A monkey comes along and pulls the shingles off in 9 hours. How long does it take Tom, Jack and the monkey to shingle one roof?
I tried 3/4t + t -1/9t = x
1 solutions

Answer 355533 by ankor@dixie-net.com(15623) About Me  on 2011-12-11 07:25:25 (Show Source):
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Tom and Jack are shingling a roof.
Tom takes 75% of the time Jack does to shingle a roof.
Together they finish the roof in 5 hours.
A monkey comes along and pulls the shingles off in 9 hours.
How long does it take Tom, Jack and the monkey to shingle one roof?
:
let t = time required when all three are on the job
let the completed job = 1 (a shingled root)
we can replace Tom & jack with 5 hrs, a simple shared work equation then:
:
t%2F5 - t%2F9 = 1
multiply by 45 and we have
9t - 5t = 45
4t = 45
t = 45%2F5
t = 11.25 hrs. 11 hrs 15 min


Travel_Word_Problems/545126: At noon, the cruise ship Celebration is 60 miles due south of the cruise ship Inspiration and is sailing north at a rate of 30 mph. If the inspiration is sailing west at a rate of 20 mph, find the time at which the distance d between the ships is a minimum. What is this distance?
1 solutions

Answer 355489 by ankor@dixie-net.com(15623) About Me  on 2011-12-10 22:08:59 (Show Source):
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At noon, the cruise ship Celebration is 60 miles due south of the cruise ship Inspiration and is sailing north at a rate of 30 mph.
If the inspiration is sailing west at a rate of 20 mph, find the time at which the distance d between the ships is a minimum.
:
let t = the travel time in hrs of both ships
then
30t = travel dist of the Celebration (sailing north toward the ref point)
20t = travel dist of the Inspiration (sailing west from the ref point)
:
The two ships course form a right triangle from the ref point
The distance between the two ships, is the hypotenuse (d)
d^2 = (60-30t)^2 + (20t)^2
:
d^2 = 3600 - 1800t - 1800t + 900t^2 + 400t^2
d^2 = 3600 - 3600t + 1300t^2
d = sqrt%281300t%5E2+-+3600t+%2B+3600%29
we can ignore the square root when we find the axis of symmetry
t = -%28-3600%29%2F%282%2A1300%29
t = 3600%2F2600 = 18%2F13
t = 1.3846 hrs the distance between them will be minimum
:
What is this distance?
Find the distance each ship is from the ref point in 1.3846 hrs
60-(30*1.3846) = 18.46, northbound Celebration
1.3846*20 = 27.7, westbound Inspiration
:
Find the distance between the ships at this time
d = sqrt%2818.46%5E2+%2B+27.7%5E2%29
d = 33.3 mi apart at this time




Exponential-and-logarithmic-functions/545106: how do we solve log16-log2x=4?
1 solutions

Answer 355484 by ankor@dixie-net.com(15623) About Me  on 2011-12-10 21:31:47 (Show Source):
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solve log(16) - log(2x) = 4
subtraction means divide, so write
log%28%2816%2F%282x%29%29%29 = 4
Simplify,cancel 2
log%28%288%2Fx%29%29 = 4
write the exponent equiv of logs
10%5E4 = 8%2Fx
10000x = 8
x = 8%2F10000
x = .0008
:
:
Check this on your calc: enter log(16) - log(2*.0008), results: 4


Rate-of-work-word-problems/544724: Two crews can complete a job in 45 days when working together. On their own, one crew completes the same job in 80 days. How long would it take the other crew to complete the same job on their own?
1 solutions

Answer 355481 by ankor@dixie-net.com(15623) About Me  on 2011-12-10 21:24:14 (Show Source):
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Two crews can complete a job in 45 days when working together.
On their own, one crew completes the same job in 80 days.
How long would it take the other crew to complete the same job on their own?
:
let t = time required by the 2nd crew alone
let the completed job = 1
:
The two crews each do a fraction of the job, the two fractions add up to 1
:
45%2F80 + 45%2Ft = 1
multiply by 80t, results:
45t + 80(45) = 80t
3600 = 80t - 45t
3600 = 35t
t = 3600%2F35
t = 102.857 days, crew two alone
:
:
:
See if that checks out
45%2F80 + 45%2F102.857 =
.5625 + .4375 = 1


Graphs/544675: I need help graphing the following equations:
2x+5y=12
4x+3y=2
3x-2y=10
If you could help me graph the first one, I am sure I could figure out the rest.
Thank you,
Emily
1 solutions

Answer 355454 by ankor@dixie-net.com(15623) About Me  on 2011-12-10 19:08:04 (Show Source):
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In order plot a graph, we want the equation in the slope/intercept form, y = mx + b
:
2x + 5y = 12
5y = -2x + 12
divide both sides by 5
y = -2%2F5x + 12%2F5
this will work OK using decimals
y = -.4x + 2.4
:
Choose a couple values for x and find y:
x = -3
y = -.4(-3) + 2.4
y = +1.2 + 2.4
y = 3.6
:
x = +3
y = -.4(3) + 2.4
y = -1.2 + 2.4
y = + 1.2
:
x | y
--------
-3 | 3.6
+3 | 1.2
Should look like this
+graph%28+300%2C+200%2C+-5%2C+8%2C+-5%2C+5%2C+-.4x%2B2.4%29+


Functions/544946: I'm takng a test today and I need help on functions because they are confusing please help me if you can i'm in 8th grade doing high school work please help me
1 solutions

Answer 355374 by ankor@dixie-net.com(15623) About Me  on 2011-12-10 13:09:44 (Show Source):
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You have to submit a specific problem for us to help you here.


real-numbers/544575: A man had dollar bills and 5 cent coins,he spent 1/3 of his money and had < $50 left,he now has 4 times as many dollars as he had 5 cent pieces and half as many 5 cent pieces as he had dollars.How much did he start with and spend ? Thanks.I am not sure how to asign values @ the start.How about 10 x + y ?
1 solutions

Answer 355350 by ankor@dixie-net.com(15623) About Me  on 2011-12-10 09:47:50 (Show Source):
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A man had dollar bills and 5 cent coins, he spent 1/3 of his money and had < $50 left, he now has 4 times as many dollars as he had 5 cent pieces and half as many 5 cent pieces as he had dollars.
How much did he start with and spend?
:
Not alot of information here, we will have to depend on the fact that an integer solution will be unique.
:
Let d = no. of dollar bills
Let n = no. 5 cents coins
1d + .05n = original amt
then
2%2F3(1d+.05n) = amt left after spending 1/3 of it
:
"he now has 4 times as many dollars as he had 5 cent pieces and half as many 5 cent pieces as he had dollars."
2%2F3(1d + .05n) = 4(n) + .5(.05d)
2%2F3(1d + .05n) = 4n + .025d
multiply both sides by 3
2(1d + .05n) = 3(4.00n + .025d)
2d + .10n = 12n + .075d
2d - .075d = 12n - .10n
1.925d = 11.9n
d = 11.9%2F1.925n
Put this equation into a graphing calc
y = 11.9%2F1.925x, the table show only one integer solution, keeping the <$50 rule in mind, for y which represent the original no. of dollars, d=68 and x is the no. of nickels, n=11
:
the original amt then is: 68 + 11(.05) = $68.55
:
Find the amt spent, he now has 4(11) = 44, .05(68/2) = 1.70. Total 45.70
therefore he spent, 68.55 - 45.70 = $22.85
:
:
Check our solution by confirming the amt spent is 1/3 the original:
22.85%2F68.55 = 1%2F3; confirms our solution
:
:
Did this make sense to you?


Proportions/544858: How do I determine if the quantity of each pair of ratios are porportional in 9/5 = 27/15. My email address is lavernec3@yahoo.com and I am helping my 11 year old son with his home work.
1 solutions

Answer 355283 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 21:59:10 (Show Source):
You can put this solution on YOUR website!
One way is just cross multiply
9%2F5 = 27%2F15
9*15 = 5*27
135 = 135, equal, they are the same proportion


Equations/544844: Jamie can solve 2 equations in a minute. Mackey can solve 3 equations in a minute. Jamie starts working at 10 A.M. and Mackey starts working at noon. What time will Mackey have solved as many problems as Jamie?
1 solutions

Answer 355275 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 21:49:00 (Show Source):
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Jamie can solve 2 equations in a minute. Mackey can solve 3 equations in a minute.
Jamie starts working at 10 A.M. and Mackey starts working at noon.
What time will Mackey have solved as many problems as Jamie?
:
Let m = no. of minutes worked by Mackey (who started at noon)
then
(m + 120) = no. of minutes worked by Jamie
:
3m = 2(m + 120)
3m = 2m + 240
3m - 2m = 240
m = 240 minutes which is 4 hrs
:
They will have worked the same number equations at 4 PM


Linear-equations/544770: Find the equation of the line containing the following points (7,-11)(3,5). Make sure the equation is in slope-intercept form.
thanks

1 solutions

Answer 355239 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 20:01:48 (Show Source):
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Find the equation of the line containing the following points (7,-11)(3,5).
Assign the given values as follows
x1=7, y1=-11
x2=3, y2=5
:
Use slope formula: m = %28%28y2-y1%29%29%2F%28%28x2-x1%29%29
so we have
m = %28%285-%28-11%29%29%29%2F%28%283-7%29%29 = %28%285%2B11%29%29%2F%28%28-4%29%29 = -16%2F4 = -4 is the slope
:
Use the point/slope formula y - y1 = m(x - x1)
y - (-11) = -4(x - 7)
y + 11 = -4x + 28
y = -4x + 28 - 11
y = -4x + 17, is the slope/intercept equation


Rational-functions/544732: Could someone help with this please? I have to find the inverse and graph the function and its inverse on the same coordinate plane.
Y= (index 3 radicand x)/2
1 solutions

Answer 355232 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 19:39:58 (Show Source):
You can put this solution on YOUR website!
We can write it:
Y = 3sqrt%28x%29%2F2
:
Find the inverse, swap x for y and solve for x
x = 3sqrt%28y%29%2F2
multiply both sides by 2
2x =3sqrt%28y%29
Cube both sides
(2x)^3 = y
we can also write it
y = 8x^3 is the inverse
:
The graph
+graph%28+300%2C+300%2C+-2%2C+2%2C+-2%2C+2%2C+%28x%5E%281%2F3%29%29%2F2%2C+8x%5E3%29+
For some reason I could not make the negative portion of the original equation come up on this, plot these two equations on a graphing calc to see it.
y = (x^(1/3))/2
y = 8x^3


Expressions-with-variables/544678: I need to resolve this equation by substitution:
3(x-1) + 2(y+3) = 8
4x - (y-6) = 9
I don't know how! The answer is supposed to be x = 1 and y = 1

Thank you
1 solutions

Answer 355224 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 19:09:45 (Show Source):
You can put this solution on YOUR website!
3(x-1) + 2(y+3) = 8
4x - (y-6) = 9
:
simplify both equations
3x - 3 + 2y + 6 = 8
3x + 2y + 3 = 8
3x + 2y = 8 - 3
3x + 2y = 5
and
4x - y + 6 = 9
-y = -4x + 9 - 6
-y = -4x + 3
Make y positive, mult by -1
y = 4x - 3;
use this for substitution in the 1st equation
3x + 2y = 5
3x + 2(4x-3) = 5
3x + 8x - 6 = 5
11x = 5 + 6
11x = 11
x = 11/11
x = 1
Find y, using eq: y = 4x - 3
y = 4(1) - 3
y = 4 - 3
y = 1


Travel_Word_Problems/544326: a train wheel with a diameter of 2 feet makes 10,000 revolutions per hour. At approximately what speed in miles per hour is the train traveling.
1 solutions

Answer 355197 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 14:26:49 (Show Source):
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a train wheel with a diameter of 2 feet makes 10,000 revolutions per hour.
At approximately what speed in miles per hour is the train traveling.
:
Find how many feet the wheel travels in one hrs. Divide that by 5280
:
%28%28pi%2A2%2A10000%29%29%2F5280 = 11.9 mph


absolute-value/544320: Please help!
I don't understand how to do this equation:
2|d+3|=8
or
1.2|5p|=3.6

1 solutions

Answer 355159 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 09:11:50 (Show Source):
You can put this solution on YOUR website!
2|d+3| = 8
simplify first, divide both sides 2 and you have
|d + 3| = 4
Two solution for d, when we remove the abs
d + 3 = 4
d = 4 - 3
d = 1
and
d + 3 = -4
d = -4 - 3
d = -7
It helps you to understand if we replace both solutions for d in the original problem
d=1
2|1+3| = 8
2*4 = 8
and d=-7
2|-7+3| = 8
2|-4| = 8
removing the abs, always results in a positive, therefore:
2*4 = 8
:
:
1.2|5p| = 3.6
divide both sides by 1.2, results:
|5p| = 3
two solution
5p = +3
p = 3/5
and
5p = -3
p = -3/5
You can check both solutions in the original problem for this one.


test/544475: Della is at a point three miles from her home. She starts riding her bike 1/4 mile per minute toward home.
How long will it take her to be half a mile from home?
How long will it take her to get home?
1 solutions

Answer 355157 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 08:59:54 (Show Source):
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Della is at a point three miles from her home.
She starts riding her bike 1/4 mile per minute toward home.
How long will it take her to be half a mile from home?
How long will it take her to get home?
:
Find how long it take her to get home, from the information, we know it takes 4 min to ride 1 mile, therefore:
3 * 4 = 12 minutes for the trip
:
We know that it takes her 2 min to ride 1/2 mi, therefore:
12 - 2 = 10 min, to be a 1/2 mi from home


Volume/544318: If the length of each side of a cube is doubled, by what factor did the volume increase
1 solutions

Answer 355155 by ankor@dixie-net.com(15623) About Me  on 2011-12-09 08:51:03 (Show Source):
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If the length of each side of a cube is doubled, by what factor did the volume increase
:
By 8, (2^3)