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Answer 108212 by Fombitz(13828) on 2008-07-10 16:38:09 (Show Source):
You can put this solution on YOUR website!A quadratic function has a general form of

A quadratic function has a maximum value where its derivative equals 0.
The derivative of f(x) is,

So now add your values that you know,

1. 
and for the maximum value,

2. 
Generally, you need three points to solve for a quadratic equation.
We can solve for the other two variables in terms of one variable.
From eq. 2,
2.

Then from eq.1,
1.

So the general form of the solution is,

There are some limits on a also.
Since the value at x=3 is a maximum, then a<0.

Here are three graphs for a=-.5,-1,-2 just to give a sense of the family of solutions.
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Triangles/147838: I got an answer for this, but I'm not sure if i'm right. thanks!!!!
Standing on a cliff 380 meters above the sea, Sue sees an approaching ship and measures its angle of depression, obtaining 9 degrees. How far from the shore is the ship?
Now Sue sights a second ship beyond the first. The angle of depression of the second ship is 5 degrees. How far apart are the 2 ships?
My answer was about 2399.226 meters away, and 1944.194 meters apart. 1 solutions
Answer 108210 by Fombitz(13828) on 2008-07-10 16:10:01 (Show Source):
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Coordinate-system/147837: I don't understand this: find the value of k if the line joining (4,k) and (3,1) is parallel to the line y=-1/2x-9/2 1 solutions
Answer 108209 by Fombitz(13828) on 2008-07-10 16:06:38 (Show Source):
You can put this solution on YOUR website!If lines are parallel, it means their slopes are equal.
The line has a slope of (-1/2).
The formula for the slope given two points is,

For parallel lines, set the slope equal to (-1/2) and solve for k.

Here is a graph of the line, the two points and the new line.
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Linear-equations/147809: solve the system of equations by graphing.then classify the system as consistent or inconsistant, dependant or independant;
7x-8y=-16
8y-7x=16 1 solutions
Answer 108194 by Fombitz(13828) on 2008-07-10 11:13:14 (Show Source):
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Quadratic-relations-and-conic-sections/147722: Please solve, show work and include all relevant points (i.e vertices, intercepts, foci,directrix,asymptotes, ect..)
x^2-4y^2+2x=32y=67 1 solutions
Answer 108193 by Fombitz(13828) on 2008-07-10 11:09:09 (Show Source):
You can put this solution on YOUR website!
Complete the square in both x and y.

This is an equation for a hyperbola which has a general form of

Center of the hyperbola is (h,k) or in this case (-1,-4)
Distance between the foci is 2c where

The eccentricity,e, is then

The foci of the hyperbola are located at
(  ,  )=(  ,  )
The vertices of the hyperbola are located at
(  ,  )=(  ,  )=(-3,-4) and (1,-4)
The equation of the asymptote lines is given by
The directrix of a hyperbola is given by
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Linear-equations/147805: graph the equation using the slope and y intercept;
y=7/5x+2 1 solutions
Answer 108191 by Fombitz(13828) on 2008-07-10 10:00:58 (Show Source):
You can put this solution on YOUR website!
The y intercept occurs when x=0.
At x=0, then

Plot (0,2) on the graph

Now starting at (0,2) use the slope to find another point.
Slope is rise (change in y) over run (change in x).
Starting at (0,2) with a slope of (7/5) would give you,
y:Starting y + Change in y=2+7=9
x:Starting x + Change in x=0+5=5
Plot (5,9) on the graph.

Then draw the line joining the two points.

To complete the graph, extend the line in both directions, from the points.
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Linear-equations/147753: This question is from textbook
use the echelon method to solve.
x + y/3 = -6
x/5 + y/4 = -7/4 1 solutions
Answer 108189 by Fombitz(13828) on 2008-07-10 09:30:08 (Show Source):
You can put this solution on YOUR website!1.
2. 
or in matrix form,

Multiply eq. 1 by (-1/5) and add to eq. 2, to remove x.

2'. 
2'. 
Now your two equations, in echelon form, are
1.
2'. 
or in matrix form,
You can solve for y from 2'.
2'.

From 1,
1.
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Exponential-and-logarithmic-functions/147790: g(x)=e^x+3
Description of transformation: Equation(s) from Horizontal Asymptote(s): y-intercept in (x,y) form:
I am not sure what this is asking me to do? Help
1 solutions
Answer 108188 by Fombitz(13828) on 2008-07-10 08:51:42 (Show Source):
You can put this solution on YOUR website!Here's a graph of your equation.

Let me see if I can decipher what you need.
.
.
.
Horizontal asymptote.
From the equation,

as x becomes large (negative), the exponent term quickly goes to 0,
 as x approaches 
As x goes to negative infinity, the horizontal asymptote is y=3.

It's shown here as the blue line.
.
.
.
The y intercept in (x,y) form is the point that the graph crosses the y axis.
In that case
 and

In (x,y) format that would be (0,4).
The y-intercept is shown as the green circle.
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Age_Word_Problems/147671: A man and his brother have a combined age of 164 years. 46 years ago, the man was 7 times as old as his brother. How old is the man? How old is the brother? 1 solutions
Answer 108041 by Fombitz(13828) on 2008-07-09 11:13:20 (Show Source):
You can put this solution on YOUR website!Man's age is M.
Brother's age is B.
1. 
46 years ago the man's age was M-46.
46 years ago his brother age was B-46.
2. 
We can use eq. 1 to solve for M in terms of B.
Then substitute this into eq. 2.
1.

Now substitute.
2.

Then from eq. 1,

The man is 109 years old and his brother is 55.
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Numbers_Word_Problems/147664: hello again i have a problem i need help with. the sum of two numbers is 89 adding four times the first number to the second number gives 155 which one of the equations expresses this problem algebraically? A. (X-89)+4X=155 B. 89+4x=155 C.4x+(89-x)=155 D.4(89+x)+x=155 i picked B thank you for all of your help 1 solutions
Answer 108034 by Fombitz(13828) on 2008-07-09 10:24:25 (Show Source):
You can put this solution on YOUR website!It would be more helpful if you wrote down the steps that got you to your answer.
Anyways, let's go through it step by step.
First name your unknown numbers.
We'll use x and y.
"The sum of two numbers is 89."
1. 
adding four times the first number to the second number gives 155
2. 
Now you have two equations.
You can use eq. 1 to substitute for y in eq. 2,
1.

Now substitute into eq. 2,
2.

This line looks like C.
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Graphs/147659: Hope someone can help me with this.
a. An financial advisor invested a total of $6,000, part at 4% annual simple interest and part at 6.5% annual simple interest.
The amount of interest earned for 1 year was $335.00. How much was invested at each rate? Show work.
b. Consider the equation 3x2 – 4x + 7 = 0.
1.Find the discriminant, b2 – 4ac, and then determine whether one real-number solution, two different real-number solutions, or two different imaginary-number solutions exist.
2. Use the quadratic formula to find the exact solutions of the equation. Show work.
1 solutions
Answer 108027 by Fombitz(13828) on 2008-07-09 09:47:24 (Show Source):
You can put this solution on YOUR website!a.)Let's call the amount invested at 4%, A, and
call the amount invested at 6.5%, B.
What do we know?
The total invested was $6000.
1. 
After one year the total interest was $335.
2. 
Let's multiply both sides of eq. 2 by 100 to get rid of denominators.
2. 
Now we can use eq. 1 to get A in terms of B and substitute into eq. 2,
1.

Now substitute into eq. 2,
2.

From eq. 1,

.
.
.
b1)3x2 – 4x + 7 = 0
The quadratic formula deals with an equation of the form,

in your case,

The discriminant is,

Since the discriminant is negative, there are two imaginary, or complex roots, that solve the equation.
.
.
.
b2) The full quadratic formula is
The exact solution is,

The approximation is,
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Rational-functions/147096: The question is to find the vertical and horizontal asymptote(s) of
f(x)= (x^3+8)/(x^2+4)
1 solutions
Answer 107438 by Fombitz(13828) on 2008-07-02 16:17:13 (Show Source):
You can put this solution on YOUR website!There are no vertical asymptotes, the denominator does not go to zero.
There are no horizontal asymptotes, as x goes to infinity, the function looks like y=x, as you can see from the graph below.

The second graph shows the behavior of the graph near zero.
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Geometry_Word_Problems/147101: Please help me solve this word problem step-by-step.
(((The Perimeter of the rectangular is 320ft if the length is 5ft longer than twice the width. Find its length and width.))) 1 solutions
Answer 107437 by Fombitz(13828) on 2008-07-02 16:14:15 (Show Source):
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Graphs/147097: The question is to find the vertical and horizontal asymptote(s)
f(x)=(x^3+3x^2)/(x^2-4) 1 solutions
Answer 107435 by Fombitz(13828) on 2008-07-02 16:06:08 (Show Source):
You can put this solution on YOUR website!Vertical asymptotes occur whenever the denominator goes to zero.
In this case,
 when
 and 
There are no horizontal asymptotes for this function.
As x goes to positive and negative infinity, the graph begins to look like y=x.
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Geometry_Word_Problems/147098: Please help me to solve this word problem in step-by-step process.(((Ron found that his car used 7 gallons of gas to travel 200 miles. He plans to drive 1300 miles from his home to Denver, Colorado. How many gallons of gas will he use if his car continues to consume gas at the same rate? Round to the nearest gallon.))) 1 solutions
Answer 107434 by Fombitz(13828) on 2008-07-02 15:56:44 (Show Source):
You can put this solution on YOUR website!Set up a ratio.
7 gallons is to 200 miles as x gallons is to 1300 miles.
Mathematically, that is,

To the nearest gallon, that would be 46 gallons.
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Equations/147022: Add or subtract the fractions. Express the answer in simplest form:
A: [4/(x-2)]+[3/x^2-x-2]
B: [4y/(y^2+6y+5)]-[2y/(y^2-1)] 1 solutions
Answer 107404 by Fombitz(13828) on 2008-07-02 10:39:25 (Show Source):
You can put this solution on YOUR website!A: 
Remember, to add or subtract fractions you need a common denominator.
Luckily,

So you can multiply, the first term by (x+1)/(x+1) to get it done.
A: 
A: 
A: 
A: 
B: 
Let's look at both denominators and factor them.
First term denominator:

Second term denominator:

Multiply the first term by (y-1)/(y-1) and
then multiply the second term by (y+5)/(y+5) to get
the common denominator (y+1)(y-1)(y+5).
B: 
B: 
B: 
B:
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Money_Word_Problems/147066: Examine the rise in gasoline prices from 1997 to 2006. The price of regular unleaded gasoline in January 1997 was $1.26 and in January 2006 the price of regular unleaded gasoline was $2.31 (Bureau of Labor Statistics, 2006). Use the coordinates (1997, 1.26) and (2006, 2.31) to find the slope (or rate of change) between the two points. Describe how you arrived at your answer 1 solutions
Answer 107402 by Fombitz(13828) on 2008-07-02 10:07:44 (Show Source):
You can put this solution on YOUR website!The slope or rate of change would be the change in gas price (in dollars) divided by the change in time (years in this case).
In equation form,

where GP is gas price and Y is year.

The units of the rate of change are $/year.
On average, the price of gas from 1997 to 2006 rose almost 12 cents per year.
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