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Polynomials-and-rational-expressions/104756: Factor completely. x^2 + 7x – 30 1 solutions
Answer 76242 by Fombitz(13828) on 2007-10-17 16:03:54 (Show Source):
You can put this solution on YOUR website!Look for a solution

When the equation is expanded with a,b,

Compare that to your equation and you find that,

Look for integer factors (a,b) of 30
(1,30)
(2,15)
(3,10)
(5,6)
Factors (3,10) look promising since their difference is 7.
Now to get the signs right.
The smaller number needs to be negative for the sum to positive.
(a,b)=(-3,10)
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Polynomials-and-rational-expressions/104761: The profit on a watch is given by P = x^2 – 13x – 80, where x is the number of
watches sold per day. How many watches were sold on a day when there was a
$50 loss? 1 solutions
Answer 76241 by Fombitz(13828) on 2007-10-17 15:52:34 (Show Source):
You can put this solution on YOUR website!For a $50 loss, then the profit was -50.
Find x such that P(x)=-50.

Two solutions
x=15 and x=-2.
Selling (-2) watches doesn't make sense, so your only answer is 15 watches sold.
Check your answer.

Good answer.
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Graphs/104744: PLEASE HELP!!!!!
L HAS Y-INTERCEPT (0,-3) AND IS PARALLEL TO THE LINE WITH THE EQUATION Y= 2/3x + 1 1 solutions
Answer 76233 by Fombitz(13828) on 2007-10-17 15:36:26 (Show Source):
You can put this solution on YOUR website!Parallel lines have the same slope.
For your line, when x=0, y=-3.
Using the point-slope equation of a line,

We can use your information and substitute.
 .
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Mixture_Word_Problems/104741: for the floor plans given in exercise determine whether the side through the points (2,3) and (11,6) is perpendicular to the side through the points (2,3) and (-3, 18).
THE FLOOR PLANS IN THE GIVEN EXERCISE ARE (2,3), (11,6), (-3, 18) AND (8,21) 1 solutions
Answer 76231 by Fombitz(13828) on 2007-10-17 15:33:28 (Show Source):
You can put this solution on YOUR website!Line 1 is through (2,3) and (11,6).
Line 2 is through points (2,3) and (-3, 18).
For lines to be perpendicular, their slopes are negative reciprocals,
 or

Let's calculate the slope of both lines and see if this relationship holds.
The formula for the slope is :

For Line 1,

For Line 2,

When we look at the product of their slopes

We find that they are negative reciprocals and therefore the lines are perpendicular, as you can see by the graph below.
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Rectangles/104654: This question is from textbook
W x (L=9) = 36 2
length is 9 inches greater than the width area 36in2.
Can you please break down how this is done (the formula).
Thank you 1 solutions
Answer 76226 by Fombitz(13828) on 2007-10-17 15:15:58 (Show Source):
You can put this solution on YOUR website!The area of a rectangle is equal to A=L*W.
The area of your rectangle is 36 sq.inches.
Your first equation is
1. 
You say that the length is 9 inches greater than the width, or
2. 
Substitute your equation (2) into (1) and solve for W.
 Distributive property.
 Additive inverse of 36.
 Factor the quadratic equation.
Solutions are
W=-12, W=3.
Since a negative width does not make sense, we throw out that solution.
W=3 inches

L=12 inches
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Polynomials-and-rational-expressions/104687: page 330 # 64 - factor each polynomial
x^2 - 5xs -24s^2 1 solutions
Answer 76216 by Fombitz(13828) on 2007-10-17 14:11:44 (Show Source):
You can put this solution on YOUR website!We want to find the values for a and b that make this true.

If we expand the equation in terms of a and b, we can find what relationships need to be met to solve the problem.
Note, the terms a and b will also include an s term for each.
Don't let that throw you off, it acts like a constant.

Let's compare terms in the original equation:
1.  or

2. 
Let's use equation 2 and look for factors of  that when summed equal -5s (Equation 1).
Integer factors of  are (1s,24s),(2s,12s),(3s,8s),(4s,6s).
(3s,8s) looks promising since their difference is 5s.
Now we need to get the signs right.
 and
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Miscellaneous_Word_Problems/104723: A homeowner has 120 feet of fence to enclose a rectangular garden.
Come up with a function that gives the area of the garden as a function of the width (Area in terms of width).
What I know
length*2 + width*2=120 feet 2W=120-2L Divide everything by 2
W=60-L
Is this complete or do I need to do something else for the answer? Thank you. 1 solutions
Answer 76214 by Fombitz(13828) on 2007-10-17 13:21:51 (Show Source):
You can put this solution on YOUR website!Yes, you still need to come up with the area equation for the rectangular garden using width and length.
Once you have the area equation, substitute for width, with (60-L), as you derived.
You're almost there.
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Square-cubic-other-roots/104710: x-2*sqrt(x-3)=3
solve for zero...
I subtract x from both sides which =
-2*sqrt(x-3)=3-x
then I divide by -2 from both sides
sqrt(x-3)=(3-x)/-2
then to get rid of the "sqrt" ^2 on both sides
x-3=(9+x^2)/4
then I subtract "x" and add 3 to both sides to solve for zero.
0=(9+x^2)/4-x+3
then I find a common denominator of 4 and solve
0=(9+x^2)/4 -4x/4+12/4 which equals 0=(x^2-4x+21)/4
then I multiply 4/1 on both side the loose the denominator.
0=x^2-4x+21 which can not be factored, but my text book gives a solution set of {7,3}. I cant find were I went wrong, please help.
Please note, this question had already been answered but the link to the answer did not work so this is why I am re-submitting it. Thank you. 1 solutions
Answer 76201 by Fombitz(13828) on 2007-10-17 11:13:26 (Show Source):
You can put this solution on YOUR website!Here's the step where you got on the wrong path.
You're missing a term.

Re-work  and continue from there.
You're on the right track otherwise.
Post another question if you get stuck.
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Signed-numbers/104707: What is the arithmetic mean of 8,7,7,5,3,2, and 2? 1 solutions
Answer 76200 by Fombitz(13828) on 2007-10-17 11:07:53 (Show Source):
You can put this solution on YOUR website!The arithmetic mean is the sum of all of the numbers divided by the total count of numbers.
The sum of all of the numbers
The total count of all numbers
 You have seven numbers.
Mean = 34/7 = 4.86 (rounded off to two decimal places).
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Miscellaneous_Word_Problems/104704: Train A leaves a station traveling at 32 kilometers per hour. 4 hours later, train B leaves the same station traveling in the same direction at 52 kilometers per hour. How long does it take train B to catch up to train A? 1 solutions
Answer 76199 by Fombitz(13828) on 2007-10-17 11:03:41 (Show Source):
You can put this solution on YOUR website!Rate x Time = Distance
Train A rate : 32 km/h
Train A time : t+4 hrs (it's 4 hours ahead of train B)
Train A distance : 32(t+4)
Train B rate : 52 km/h
Train B time : t hrs
Train B distance : 52t
Train B catches Train A when the distances from the station is equal.
 Additive inverse of 32t
 Simplify
 Multiplicative inverse of 20.
 hours
Always check your answer:
Train A travels 32(t+4) km

Train B travels 52t km

Train A distance = Train B distance.
Good answer.
t=32/5 hours
or 6.4 hours
or 6 hrs 24 min
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Linear-equations/104697: David has $16,000 to invest. He invests $11,000 in a mutual fund that pays 12% annual simple interest. If he wants to make a t least $2200 in yearly interest, at what minimum rate does the remainder of the money need to be invested?
This was my hardest one. 1 solutions
Answer 76197 by Fombitz(13828) on 2007-10-17 10:30:30 (Show Source):
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logarithm/104689: Could someone please assist me by solving this logarithmic equation step-by-step for future reference. Thank you.
log(7y + 1) = 2log(y+3)-log2
1 solutions
Answer 76196 by Fombitz(13828) on 2007-10-17 10:17:40 (Show Source):
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Linear-equations/104683: A basketball court is a rectangle with a perimeter of 86 meters. The length is 13 meters more than the width. Find the width and length of the basketball court.
I don't know where to start, please help. 1 solutions
Answer 76191 by Fombitz(13828) on 2007-10-17 08:53:29 (Show Source):
You can put this solution on YOUR website!Start with what you know.
Court is a rectangle with width and length.
Give the variables a name.
W-width
L-length
What is the perimeter of a rectangle in terms of its width and length?
P=2L +2W
Now look at the specifics of the information you are given.
The perimeter is 86.
P=2L+2W=86
The length is 13m more than the width.
L=13+W
So now you have two equations, with two unknowns.
1. 
2. 
Substitute equation 2 in equation 1 and solve for W.
1.

Use this result in equation 2 to solve for L.
2.

Verify your answer

Good answer.
L=28 m and W=15 m
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Exponents/104571: What is 2 to the negative 5 times 4 to the negative 3 ? I'm getting an answer in decimal form....4.8828125 to the negative 04 .Please help 1 solutions
Answer 76092 by Fombitz(13828) on 2007-10-16 17:12:32 (Show Source):
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Linear_Equations_And_Systems_Word_Problems/104568: Hello,
I need help with this problem:
The height, in feet, of a rocket t seconds after blast-off is given by a formula h=1260t-16t^2. After how many seconds will the rocket first reach a height of 23,400 feet?
Thank you 1 solutions
Answer 76091 by Fombitz(13828) on 2007-10-16 17:06:39 (Show Source):
You can put this solution on YOUR website!

Use the quadratic formula,

where
a=-16, b=1260, and c=-23400
 and

t=48.75 seconds
t=30 seconds
Since your looking for the first time, pick the earliest time.
t=30 seconds.
Why two answers? First when the rocket is going up and then when the rocket's coming down, as shown in the graph below, with the horizontal axis equal to h=23,400 feet.
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